diff --git a/src/browser/components/AddSectionButton/AddSectionButton.tsx b/src/browser/components/AddSectionButton/AddSectionButton.tsx
deleted file mode 100644
index beff820652..0000000000
--- a/src/browser/components/AddSectionButton/AddSectionButton.tsx
+++ /dev/null
@@ -1,63 +0,0 @@
-import React, { useState, useRef, useEffect } from "react";
-import { Plus } from "lucide-react";
-// import { Tooltip, TooltipTrigger, TooltipContent } from "../Tooltip/Tooltip";
-
-interface AddSectionButtonProps {
-  onCreateSection: (name: string) => void;
-}
-
-export const AddSectionButton: React.FC<AddSectionButtonProps> = ({ onCreateSection }) => {
-  const [isCreating, setIsCreating] = useState(false);
-  const [name, setName] = useState("");
-  const inputRef = useRef<HTMLInputElement>(null);
-
-  useEffect(() => {
-    if (isCreating && inputRef.current) {
-      inputRef.current.focus();
-    }
-  }, [isCreating]);
-
-  const handleSubmit = () => {
-    const trimmed = name.trim();
-    if (trimmed) {
-      onCreateSection(trimmed);
-    }
-    setName("");
-    setIsCreating(false);
-  };
-
-  if (isCreating) {
-    return (
-      <div className="flex items-center px-2 py-0.5">
-        <input
-          ref={inputRef}
-          type="text"
-          value={name}
-          onChange={(e) => setName(e.target.value)}
-          onBlur={handleSubmit}
-          onKeyDown={(e) => {
-            if (e.key === "Enter") handleSubmit();
-            if (e.key === "Escape") {
-              setName("");
-              setIsCreating(false);
-            }
-          }}
-          placeholder="Section name..."
-          data-testid="add-section-input"
-          className="bg-background/50 text-foreground ml-6 min-w-0 flex-1 rounded border border-white/20 px-1.5 py-0.5 text-[11px] outline-none select-text"
-        />
-      </div>
-    );
-  }
-
-  return (
-    <button
-      onClick={() => setIsCreating(true)}
-      data-testid="add-section-button"
-      className="text-muted/60 hover:text-muted flex w-full cursor-pointer items-center justify-center gap-1 border-none bg-transparent px-2 py-0.5 text-[11px] transition-colors"
-    >
-      <Plus size={12} />
-      <span>Add section</span>
-    </button>
-  );
-};
diff --git a/src/browser/components/ProjectSidebar/ProjectSidebar.test.tsx b/src/browser/components/ProjectSidebar/ProjectSidebar.test.tsx
index e0847ac919..c774b168e0 100644
--- a/src/browser/components/ProjectSidebar/ProjectSidebar.test.tsx
+++ b/src/browser/components/ProjectSidebar/ProjectSidebar.test.tsx
@@ -33,7 +33,6 @@ import * as ProjectDeleteConfirmationModalModule from "../ProjectDeleteConfirmat
 import * as WorkspaceStatusIndicatorModule from "../WorkspaceStatusIndicator/WorkspaceStatusIndicator";
 import * as PopoverErrorModule from "../PopoverError/PopoverError";
 import * as SectionHeaderModule from "../SectionHeader/SectionHeader";
-import * as AddSectionButtonModule from "../AddSectionButton/AddSectionButton";
 import * as WorkspaceSectionDropZoneModule from "../WorkspaceSectionDropZone/WorkspaceSectionDropZone";
 import * as WorkspaceDragLayerModule from "../WorkspaceDragLayer/WorkspaceDragLayer";
 import * as SectionDragLayerModule from "../SectionDragLayer/SectionDragLayer";
@@ -488,9 +487,6 @@ function installProjectSidebarTestDoubles() {
   spyOn(SectionHeaderModule, "SectionHeader").mockImplementation(
     (() => null) as unknown as typeof SectionHeaderModule.SectionHeader
   );
-  spyOn(AddSectionButtonModule, "AddSectionButton").mockImplementation(
-    (() => null) as unknown as typeof AddSectionButtonModule.AddSectionButton
-  );
   spyOn(WorkspaceSectionDropZoneModule, "WorkspaceSectionDropZone").mockImplementation(
     TestWrapper as unknown as typeof WorkspaceSectionDropZoneModule.WorkspaceSectionDropZone
   );
diff --git a/src/browser/components/ProjectSidebar/ProjectSidebar.tsx b/src/browser/components/ProjectSidebar/ProjectSidebar.tsx
index f89e4bd8e5..c3375028f2 100644
--- a/src/browser/components/ProjectSidebar/ProjectSidebar.tsx
+++ b/src/browser/components/ProjectSidebar/ProjectSidebar.tsx
@@ -250,6 +250,10 @@ function useWorkspaceAttentionSubscription(
 const PROJECT_ITEM_BASE_CLASS =
   "group sticky top-0 z-30 py-2 pl-2 pr-1 flex select-none items-center border-l-transparent bg-surface-primary transition-colors duration-150";
 
+// Shared classes for the chevron toggle buttons on project/section headers.
+const PROJECT_TOGGLE_BUTTON_CLASSES =
+  "text-secondary hover:bg-hover hover:border-border-light mr-1.5 flex h-5 w-5 shrink-0 cursor-pointer items-center justify-center rounded border border-transparent bg-transparent p-0 transition-all duration-200";
+
 function getProjectFallbackLabel(projectPath: string): string {
   const abbreviatedPath = PlatformPaths.abbreviate(projectPath);
   const { basename } = PlatformPaths.splitAbbreviated(abbreviatedPath);
@@ -1696,7 +1700,7 @@ const ProjectSidebarInner: React.FC<ProjectSidebarProps> = ({
                       <button
                         onClick={() => toggleProject(MULTI_PROJECT_SIDEBAR_SECTION_ID)}
                         aria-label={`${isMultiProjectSectionExpanded ? "Collapse" : "Expand"} multi-project workspaces`}
-                        className="text-secondary hover:bg-hover hover:border-border-light mr-1.5 flex h-5 w-5 shrink-0 cursor-pointer items-center justify-center rounded border border-transparent bg-transparent p-0 transition-all duration-200"
+                        className={PROJECT_TOGGLE_BUTTON_CLASSES}
                       >
                         <span className="relative flex h-4 w-4 items-center justify-center">
                           <ChevronRight
@@ -1839,7 +1843,7 @@ const ProjectSidebarInner: React.FC<ProjectSidebarProps> = ({
                             }}
                             aria-label={`${isExpanded ? "Collapse" : "Expand"} project ${projectName}`}
                             data-project-path={projectPath}
-                            className="text-secondary hover:bg-hover hover:border-border-light mr-1.5 flex h-5 w-5 shrink-0 cursor-pointer items-center justify-center rounded border border-transparent bg-transparent p-0 transition-all duration-200"
+                            className={PROJECT_TOGGLE_BUTTON_CLASSES}
                           >
                             <span className="relative flex h-4 w-4 items-center justify-center">
                               <ChevronRight
@@ -1983,11 +1987,8 @@ const ProjectSidebarInner: React.FC<ProjectSidebarProps> = ({
                             id={workspaceListId}
                             role="region"
                             aria-label={`Workspaces for ${projectName}`}
-                            className="relative pt-1"
+                            className="pt-1"
                           >
-                            {/* Vertical connector line removed — workspace status dots now
-                                align directly with the project folder icon, so the tree
-                                connector is no longer needed. */}
                             {(() => {
                               // Archived workspaces are excluded from workspaceMetadata so won't appear here
 
diff --git a/src/browser/components/WorkspaceHeartbeatModal/WorkspaceHeartbeatModal.tsx b/src/browser/components/WorkspaceHeartbeatModal/WorkspaceHeartbeatModal.tsx
index 132a9d15e9..ea0d95f426 100644
--- a/src/browser/components/WorkspaceHeartbeatModal/WorkspaceHeartbeatModal.tsx
+++ b/src/browser/components/WorkspaceHeartbeatModal/WorkspaceHeartbeatModal.tsx
@@ -11,33 +11,22 @@ import { Input } from "@/browser/components/Input/Input";
 import { Switch } from "@/browser/components/Switch/Switch";
 import { useWorkspaceHeartbeat } from "@/browser/hooks/useWorkspaceHeartbeat";
 import assert from "@/common/utils/assert";
+import {
+  clampIntervalMinutes,
+  formatIntervalMinutes,
+  HEARTBEAT_DEFAULT_INTERVAL_MINUTES,
+  HEARTBEAT_MAX_INTERVAL_MINUTES,
+  HEARTBEAT_MIN_INTERVAL_MINUTES,
+  intervalMinutesToMs,
+  parseIntervalMinutes,
+} from "@/browser/utils/heartbeatIntervalMinutes";
 import {
   HEARTBEAT_DEFAULT_CONTEXT_MODE,
   HEARTBEAT_DEFAULT_INTERVAL_MS,
   HEARTBEAT_DEFAULT_MESSAGE_BODY,
-  HEARTBEAT_MAX_INTERVAL_MS,
-  HEARTBEAT_MIN_INTERVAL_MS,
   type HeartbeatContextMode,
 } from "@/constants/heartbeat";
 
-const MS_PER_MINUTE = 60_000;
-const HEARTBEAT_MIN_INTERVAL_MINUTES = HEARTBEAT_MIN_INTERVAL_MS / MS_PER_MINUTE;
-const HEARTBEAT_MAX_INTERVAL_MINUTES = HEARTBEAT_MAX_INTERVAL_MS / MS_PER_MINUTE;
-const HEARTBEAT_DEFAULT_INTERVAL_MINUTES = HEARTBEAT_DEFAULT_INTERVAL_MS / MS_PER_MINUTE;
-
-assert(
-  Number.isInteger(HEARTBEAT_MIN_INTERVAL_MINUTES),
-  "Workspace heartbeat minimum interval must be a whole number of minutes"
-);
-assert(
-  Number.isInteger(HEARTBEAT_MAX_INTERVAL_MINUTES),
-  "Workspace heartbeat maximum interval must be a whole number of minutes"
-);
-assert(
-  Number.isInteger(HEARTBEAT_DEFAULT_INTERVAL_MINUTES),
-  "Workspace heartbeat default interval must be a whole number of minutes"
-);
-
 const HEARTBEAT_CONTEXT_MODE_OPTIONS: Array<{
   value: HeartbeatContextMode;
   label: string;
@@ -74,33 +63,6 @@ interface WorkspaceHeartbeatModalProps {
   onOpenChange: (open: boolean) => void;
 }
 
-function formatIntervalMinutes(intervalMs: number): string {
-  if (!Number.isFinite(intervalMs)) {
-    return String(HEARTBEAT_DEFAULT_INTERVAL_MINUTES);
-  }
-
-  const roundedMinutes = Math.round(intervalMs / MS_PER_MINUTE);
-  return String(clampIntervalMinutes(roundedMinutes));
-}
-
-function parseIntervalMinutes(value: string): number | null {
-  const trimmedValue = value.trim();
-  if (trimmedValue.length === 0 || !/^\d+$/.test(trimmedValue)) {
-    return null;
-  }
-
-  const minutes = Number.parseInt(trimmedValue, 10);
-  return Number.isInteger(minutes) ? minutes : null;
-}
-
-function clampIntervalMinutes(minutes: number): number {
-  assert(Number.isInteger(minutes), "Workspace heartbeat minutes must be a whole number");
-  return Math.min(
-    HEARTBEAT_MAX_INTERVAL_MINUTES,
-    Math.max(HEARTBEAT_MIN_INTERVAL_MINUTES, minutes)
-  );
-}
-
 function getValidationErrorMessage(value: string): string | null {
   const minutes = parseIntervalMinutes(value);
   if (minutes == null) {
@@ -221,7 +183,7 @@ export function WorkspaceHeartbeatModal(props: WorkspaceHeartbeatModalProps) {
 
     const didSave = await save({
       enabled: draftEnabled,
-      intervalMs: parsedMinutes * MS_PER_MINUTE,
+      intervalMs: intervalMinutesToMs(parsedMinutes),
       contextMode: draftContextMode,
       // Read directly from the textarea on save so the final keystroke is preserved even if the
       // click lands before React finishes flushing the last state update.
diff --git a/src/browser/features/Settings/Sections/HeartbeatSection.tsx b/src/browser/features/Settings/Sections/HeartbeatSection.tsx
index ee3b91db23..71ef41fdcc 100644
--- a/src/browser/features/Settings/Sections/HeartbeatSection.tsx
+++ b/src/browser/features/Settings/Sections/HeartbeatSection.tsx
@@ -2,59 +2,19 @@ import React, { useCallback, useEffect, useRef, useState } from "react";
 
 import { Input } from "@/browser/components/Input/Input";
 import { useAPI } from "@/browser/contexts/API";
-import assert from "@/common/utils/assert";
+import {
+  clampIntervalMinutes,
+  formatIntervalMinutes,
+  HEARTBEAT_MAX_INTERVAL_MINUTES,
+  HEARTBEAT_MIN_INTERVAL_MINUTES,
+  intervalMinutesToMs,
+  parseIntervalMinutes,
+} from "@/browser/utils/heartbeatIntervalMinutes";
 import {
   HEARTBEAT_DEFAULT_INTERVAL_MS,
   HEARTBEAT_DEFAULT_MESSAGE_BODY,
-  HEARTBEAT_MAX_INTERVAL_MS,
-  HEARTBEAT_MIN_INTERVAL_MS,
 } from "@/constants/heartbeat";
 
-const MS_PER_MINUTE = 60_000;
-const HEARTBEAT_MIN_INTERVAL_MINUTES = HEARTBEAT_MIN_INTERVAL_MS / MS_PER_MINUTE;
-const HEARTBEAT_MAX_INTERVAL_MINUTES = HEARTBEAT_MAX_INTERVAL_MS / MS_PER_MINUTE;
-const HEARTBEAT_DEFAULT_INTERVAL_MINUTES = HEARTBEAT_DEFAULT_INTERVAL_MS / MS_PER_MINUTE;
-
-assert(
-  Number.isInteger(HEARTBEAT_MIN_INTERVAL_MINUTES),
-  "Heartbeat minimum interval must be a whole number of minutes"
-);
-assert(
-  Number.isInteger(HEARTBEAT_MAX_INTERVAL_MINUTES),
-  "Heartbeat maximum interval must be a whole number of minutes"
-);
-assert(
-  Number.isInteger(HEARTBEAT_DEFAULT_INTERVAL_MINUTES),
-  "Heartbeat default interval must be a whole number of minutes"
-);
-
-function formatIntervalMinutes(intervalMs: number | undefined): string {
-  if (intervalMs == null || !Number.isFinite(intervalMs)) {
-    return String(HEARTBEAT_DEFAULT_INTERVAL_MINUTES);
-  }
-
-  const roundedMinutes = Math.round(intervalMs / MS_PER_MINUTE);
-  return String(clampIntervalMinutes(roundedMinutes));
-}
-
-function parseIntervalMinutes(value: string): number | null {
-  const trimmedValue = value.trim();
-  if (trimmedValue.length === 0 || !/^\d+$/.test(trimmedValue)) {
-    return null;
-  }
-
-  const minutes = Number.parseInt(trimmedValue, 10);
-  return Number.isInteger(minutes) ? minutes : null;
-}
-
-function clampIntervalMinutes(minutes: number): number {
-  assert(Number.isInteger(minutes), "Heartbeat minutes must be a whole number");
-  return Math.min(
-    HEARTBEAT_MAX_INTERVAL_MINUTES,
-    Math.max(HEARTBEAT_MIN_INTERVAL_MINUTES, minutes)
-  );
-}
-
 export function HeartbeatSection() {
   const { api } = useAPI();
   const [heartbeatDefaultPrompt, setHeartbeatDefaultPrompt] = useState("");
@@ -192,7 +152,7 @@ export function HeartbeatSection() {
       })
       .then(() =>
         api.config.updateHeartbeatDefaultIntervalMs({
-          intervalMs: clampedMinutes * MS_PER_MINUTE,
+          intervalMs: intervalMinutesToMs(clampedMinutes),
         })
       )
       .then(() => {
diff --git a/src/browser/stories/mocks/orpc.ts b/src/browser/stories/mocks/orpc.ts
index 047a97e74d..410c5ea250 100644
--- a/src/browser/stories/mocks/orpc.ts
+++ b/src/browser/stories/mocks/orpc.ts
@@ -318,7 +318,7 @@ type MockMcpTestResult = { success: true; tools: string[] } | { success: false;
 export function createMockORPCClient(options: MockORPCClientOptions = {}): APIClient {
   const {
     projects: providedProjects = new Map<string, ProjectConfig>(),
-    workspaces: inputWorkspaces = [],
+    workspaces = [],
     projectGitStatusesByWorkspace = new Map<string, ApiProjectGitStatusResult[]>(),
     workspaceActivitySnapshots = {},
     onChat,
@@ -383,7 +383,6 @@ export function createMockORPCClient(options: MockORPCClientOptions = {}): APICl
     runtimeStatuses = new Map<string, "running" | "stopped" | "unknown" | "unsupported">(),
   } = options;
 
-  const workspaces = inputWorkspaces;
   const projects = new Map(providedProjects);
   const workspaceMap = new Map(workspaces.map((w) => [w.id, w]));
 
diff --git a/src/browser/styles/globals.css b/src/browser/styles/globals.css
index 6f6d91bf80..98816a1c95 100644
--- a/src/browser/styles/globals.css
+++ b/src/browser/styles/globals.css
@@ -233,11 +233,6 @@
     --color-input-border: hsl(207 51% 59%);
     --color-input-border-focus: hsl(193 91% 64%);
 
-    /* Scrollbar */
-    --color-scrollbar-track: hsl(0 0% 18%);
-    --color-scrollbar-thumb: hsl(0 0% 32%);
-    --color-scrollbar-thumb-hover: hsl(0 0% 42%);
-
     /* Additional Semantic Colors */
     --color-muted: hsl(0 0% 53%); /* #888 - muted text */
     --color-muted-light: hsl(0 0% 50%); /* #808080 - muted light */
@@ -515,10 +510,6 @@
   --color-input-border: hsl(207 75% 52%);
   --color-input-border-focus: hsl(193 85% 56%);
 
-  --color-scrollbar-track: hsl(210 38% 95%);
-  --color-scrollbar-thumb: hsl(210 18% 78%);
-  --color-scrollbar-thumb-hover: hsl(210 18% 70%);
-
   --color-muted: hsl(210 14% 52%);
   --color-muted-light: hsl(210 20% 60%);
   --color-muted-dark: hsl(210 12% 42%);
@@ -764,10 +755,6 @@
   --color-input-border: #205ea6;
   --color-input-border-focus: color-mix(in srgb, var(--color-input-border), white 30%);
 
-  --color-scrollbar-track: #f2f0e5;
-  --color-scrollbar-thumb: #dad8ce;
-  --color-scrollbar-thumb-hover: #cecdc3;
-
   --color-muted: #6f6e69;
   --color-muted-light: #6f6e69;
   --color-muted-dark: #6f6e69;
@@ -997,10 +984,6 @@
   --color-input-border: #4385be;
   --color-input-border-focus: color-mix(in srgb, var(--color-input-border), white 22%);
 
-  --color-scrollbar-track: #1c1b1a;
-  --color-scrollbar-thumb: #343331;
-  --color-scrollbar-thumb-hover: #403e3c;
-
   --color-muted: #878580;
   --color-muted-light: #cecdc3;
   --color-muted-dark: #575653;
diff --git a/src/browser/utils/heartbeatIntervalMinutes.ts b/src/browser/utils/heartbeatIntervalMinutes.ts
new file mode 100644
index 0000000000..034ece1dfd
--- /dev/null
+++ b/src/browser/utils/heartbeatIntervalMinutes.ts
@@ -0,0 +1,69 @@
+import assert from "@/common/utils/assert";
+import {
+  HEARTBEAT_DEFAULT_INTERVAL_MS,
+  HEARTBEAT_MAX_INTERVAL_MS,
+  HEARTBEAT_MIN_INTERVAL_MS,
+} from "@/constants/heartbeat";
+
+const MS_PER_MINUTE = 60_000;
+
+export const HEARTBEAT_MIN_INTERVAL_MINUTES = HEARTBEAT_MIN_INTERVAL_MS / MS_PER_MINUTE;
+export const HEARTBEAT_MAX_INTERVAL_MINUTES = HEARTBEAT_MAX_INTERVAL_MS / MS_PER_MINUTE;
+export const HEARTBEAT_DEFAULT_INTERVAL_MINUTES = HEARTBEAT_DEFAULT_INTERVAL_MS / MS_PER_MINUTE;
+
+assert(
+  Number.isInteger(HEARTBEAT_MIN_INTERVAL_MINUTES),
+  "Heartbeat minimum interval must be a whole number of minutes"
+);
+assert(
+  Number.isInteger(HEARTBEAT_MAX_INTERVAL_MINUTES),
+  "Heartbeat maximum interval must be a whole number of minutes"
+);
+assert(
+  Number.isInteger(HEARTBEAT_DEFAULT_INTERVAL_MINUTES),
+  "Heartbeat default interval must be a whole number of minutes"
+);
+
+/**
+ * Convert a stored interval (milliseconds) to a display string in minutes.
+ * Falls back to the default when the value is missing or non-finite.
+ */
+export function formatIntervalMinutes(intervalMs: number | undefined): string {
+  if (intervalMs == null || !Number.isFinite(intervalMs)) {
+    return String(HEARTBEAT_DEFAULT_INTERVAL_MINUTES);
+  }
+
+  const roundedMinutes = Math.round(intervalMs / MS_PER_MINUTE);
+  return String(clampIntervalMinutes(roundedMinutes));
+}
+
+/**
+ * Parse a user-entered string into whole minutes, or `null` if it isn't a valid integer.
+ */
+export function parseIntervalMinutes(value: string): number | null {
+  const trimmedValue = value.trim();
+  if (trimmedValue.length === 0 || !/^\d+$/.test(trimmedValue)) {
+    return null;
+  }
+
+  const minutes = Number.parseInt(trimmedValue, 10);
+  return Number.isInteger(minutes) ? minutes : null;
+}
+
+/**
+ * Clamp whole minutes to the allowed heartbeat range.
+ */
+export function clampIntervalMinutes(minutes: number): number {
+  assert(Number.isInteger(minutes), "Heartbeat minutes must be a whole number");
+  return Math.min(
+    HEARTBEAT_MAX_INTERVAL_MINUTES,
+    Math.max(HEARTBEAT_MIN_INTERVAL_MINUTES, minutes)
+  );
+}
+
+/**
+ * Convert whole minutes back to milliseconds for storage.
+ */
+export function intervalMinutesToMs(minutes: number): number {
+  return minutes * MS_PER_MINUTE;
+}
diff --git a/src/common/utils/messages/compactionBoundary.ts b/src/common/utils/messages/compactionBoundary.ts
index bab5a9b50e..8c218932d6 100644
--- a/src/common/utils/messages/compactionBoundary.ts
+++ b/src/common/utils/messages/compactionBoundary.ts
@@ -1,13 +1,8 @@
 import assert from "@/common/utils/assert";
+import { isPositiveInteger } from "@/common/utils/numbers";
 
 import type { MuxMessage } from "@/common/types/message";
 
-function isPositiveInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value > 0
-  );
-}
-
 export function isDurableCompactedMarker(
   value: unknown
 ): value is true | "user" | "idle" | "heartbeat" {
diff --git a/src/common/utils/numbers.ts b/src/common/utils/numbers.ts
new file mode 100644
index 0000000000..1749b5efe4
--- /dev/null
+++ b/src/common/utils/numbers.ts
@@ -0,0 +1,16 @@
+/**
+ * Number type guards used across compaction, history, and workspace services
+ * to validate persisted metadata fields.
+ */
+
+export function isPositiveInteger(value: unknown): value is number {
+  return (
+    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value > 0
+  );
+}
+
+export function isNonNegativeInteger(value: unknown): value is number {
+  return (
+    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value >= 0
+  );
+}
diff --git a/src/common/utils/providers/gatewayModelCatalog.ts b/src/common/utils/providers/gatewayModelCatalog.ts
index de69d10dad..9184e08202 100644
--- a/src/common/utils/providers/gatewayModelCatalog.ts
+++ b/src/common/utils/providers/gatewayModelCatalog.ts
@@ -1,9 +1,6 @@
 import type { ProviderModelEntry } from "@/common/orpc/types";
 
-import {
-  isCopilotRoutableModel,
-  normalizeCopilotModelId,
-} from "@/common/utils/copilot/modelRouting";
+import { normalizeCopilotModelId } from "@/common/utils/copilot/modelRouting";
 import { maybeGetProviderModelEntryId } from "@/common/utils/providers/modelEntries";
 
 export function isProviderModelAccessibleFromAuthoritativeCatalog(
@@ -18,10 +15,6 @@ export function isProviderModelAccessibleFromAuthoritativeCatalog(
     return true;
   }
 
-  if (!isCopilotRoutableModel(modelId)) {
-    return false;
-  }
-
   if (!Array.isArray(models) || models.length === 0) {
     return true;
   }
diff --git a/src/node/runtime/SSHRuntime.ts b/src/node/runtime/SSHRuntime.ts
index 7db80635b8..5340bb647c 100644
--- a/src/node/runtime/SSHRuntime.ts
+++ b/src/node/runtime/SSHRuntime.ts
@@ -34,7 +34,6 @@ import { WORKSPACE_REPO_MISSING_ERROR } from "./Runtime";
 import { RemoteRuntime, type SpawnResult } from "./RemoteRuntime";
 import { log } from "@/node/services/log";
 import { runInitHookOnRuntime, runWorkspaceInitHook } from "./initHook";
-import { expandTildeForSSH as expandHookPath } from "./tildeExpansion";
 import { expandTildeForSSH, cdCommandForSSH } from "./tildeExpansion";
 import { execBuffered } from "@/node/utils/runtime/helpers";
 import { getErrorMessage } from "@/common/utils/errors";
@@ -1459,7 +1458,7 @@ export class SSHRuntime extends RemoteRuntime {
       },
       runHook: async ({ muxEnv, initLogger, abortSignal }) => {
         // Expand tilde in hook path (quoted paths don't auto-expand on remote).
-        const hookPath = expandHookPath(`${params.workspacePath}/.mux/init`);
+        const hookPath = expandTildeForSSH(`${params.workspacePath}/.mux/init`);
         await runInitHookOnRuntime(
           this,
           hookPath,
diff --git a/src/node/services/agentSession.ts b/src/node/services/agentSession.ts
index 0f5bbcacc4..7eefd50adf 100644
--- a/src/node/services/agentSession.ts
+++ b/src/node/services/agentSession.ts
@@ -4021,7 +4021,7 @@ export class AgentSession {
           if (this.ackPendingPostCompactionStateOnStreamEnd) {
             this.ackPendingPostCompactionStateOnStreamEnd = false;
             try {
-              await this.compactionHandler.ackPendingDiffsConsumed();
+              await this.compactionHandler.ackPendingStateConsumed();
             } catch (error) {
               log.warn("Failed to ack pending post-compaction state", {
                 workspaceId: this.workspaceId,
diff --git a/src/node/services/compactionHandler.ts b/src/node/services/compactionHandler.ts
index c82dd4861b..de7900a063 100644
--- a/src/node/services/compactionHandler.ts
+++ b/src/node/services/compactionHandler.ts
@@ -1,6 +1,7 @@
 import type { EventEmitter } from "events";
 import * as fsPromises from "fs/promises";
 import assert from "@/common/utils/assert";
+import { isNonNegativeInteger, isPositiveInteger } from "@/common/utils/numbers";
 import * as path from "path";
 
 import type { HistoryService } from "./historyService";
@@ -247,18 +248,6 @@ function isCompactedSummaryMessage(message: MuxMessage): boolean {
   return isDurableCompactedMarker(message.metadata?.compacted);
 }
 
-function isPositiveInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value > 0
-  );
-}
-
-function isNonNegativeInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value >= 0
-  );
-}
-
 function getNextCompactionEpoch(messages: MuxMessage[]): number {
   let epochCursor = 0;
 
@@ -462,10 +451,6 @@ export class CompactionHandler {
     await this.deletePersistedPendingStateBestEffort();
   }
 
-  async ackPendingDiffsConsumed(): Promise<void> {
-    await this.ackPendingStateConsumed();
-  }
-
   /**
    * Drop pending post-compaction state (e.g., because it caused context_exceeded).
    */
@@ -490,10 +475,6 @@ export class CompactionHandler {
     this.cachedLoadedSkills = [];
   }
 
-  async discardPendingDiffs(reason: string): Promise<void> {
-    await this.discardPendingState(reason);
-  }
-
   private async deletePersistedPendingStateBestEffort(): Promise<void> {
     try {
       await fsPromises.unlink(this.postCompactionStatePath);
diff --git a/src/node/services/heartbeatService.ts b/src/node/services/heartbeatService.ts
index 17a55c9187..57dbcf0c57 100644
--- a/src/node/services/heartbeatService.ts
+++ b/src/node/services/heartbeatService.ts
@@ -1,8 +1,7 @@
 import assert from "@/common/utils/assert";
 import type { MuxMessage } from "@/common/types/message";
 import type { ProjectsConfig, Workspace } from "@/common/types/project";
-import type { WorkspaceActivitySnapshot } from "@/common/types/workspace";
-import type { WorkspaceMetadata } from "@/common/types/workspace";
+import type { WorkspaceActivitySnapshot, WorkspaceMetadata } from "@/common/types/workspace";
 import { isWorkspaceArchived } from "@/common/utils/archive";
 import {
   HEARTBEAT_DEFAULT_INTERVAL_MS,
diff --git a/src/node/services/historyService.ts b/src/node/services/historyService.ts
index 00fa05db99..c50db80015 100644
--- a/src/node/services/historyService.ts
+++ b/src/node/services/historyService.ts
@@ -22,18 +22,7 @@ import {
   isDurableCompactionBoundaryMarker,
 } from "@/common/utils/messages/compactionBoundary";
 import { getErrorMessage } from "@/common/utils/errors";
-
-function isPositiveInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value > 0
-  );
-}
-
-function isNonNegativeInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value >= 0
-  );
-}
+import { isNonNegativeInteger, isPositiveInteger } from "@/common/utils/numbers";
 
 function hasDurableCompactionBoundary(metadata: MuxMetadata | undefined): boolean {
   if (metadata?.compactionBoundary !== true) {
diff --git a/src/node/services/workspaceService.ts b/src/node/services/workspaceService.ts
index 98df58ecf3..4b284e3786 100644
--- a/src/node/services/workspaceService.ts
+++ b/src/node/services/workspaceService.ts
@@ -54,6 +54,7 @@ import { shellQuote } from "@/node/runtime/backgroundCommands";
 import { extractEditedFilePaths } from "@/common/utils/messages/extractEditedFiles";
 import { buildCompactionMessageText } from "@/common/utils/compaction/compactionPrompt";
 import { isDurableCompactedMarker } from "@/common/utils/messages/compactionBoundary";
+import { isNonNegativeInteger, isPositiveInteger } from "@/common/utils/numbers";
 import { deriveTodoStatus } from "@/common/utils/todoList";
 import { fileExists } from "@/node/utils/runtime/fileExists";
 import { orchestrateFork } from "@/node/services/utils/forkOrchestrator";
@@ -211,22 +212,8 @@ type WorktreeArchiveSnapshotLifecycleService = Pick<
   | "restoreSnapshotAfterUnarchive"
   | "getUnsupportedUntrackedPaths"
 >;
-function normalizeHeartbeatMessageInput(message: string | undefined): string | undefined {
-  if (message == null) {
-    return undefined;
-  }
-
-  assert(typeof message === "string", "Heartbeat message must be a string when provided");
-  const trimmedMessage = message.trim();
-  if (trimmedMessage.length === 0) {
-    return undefined;
-  }
-
-  return trimmedMessage;
-}
-
-// Persisted workspace config can contain non-string or whitespace-only values; normalize the
-// message on read so an invalid override never bricks heartbeat execution.
+// Trim and normalize a heartbeat message for storage. Accepts `unknown` so it safely handles
+// both user input (string | undefined) and persisted config values that may have been corrupted.
 function sanitizeHeartbeatMessage(message: unknown): string | undefined {
   if (typeof message !== "string") {
     return undefined;
@@ -563,18 +550,6 @@ async function resetForkedSessionUsage(
   );
 }
 
-function isPositiveInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value > 0
-  );
-}
-
-function isNonNegativeInteger(value: unknown): value is number {
-  return (
-    typeof value === "number" && Number.isFinite(value) && Number.isInteger(value) && value >= 0
-  );
-}
-
 function getOldestSequencedMessage(
   messages: readonly MuxMessage[]
 ): { message: MuxMessage; historySequence: number } | null {
@@ -3292,18 +3267,12 @@ export class WorkspaceService extends EventEmitter {
 
     const message = sanitizeHeartbeatMessage(workspaceEntry.heartbeat.message);
     const contextMode = sanitizeHeartbeatContextMode(workspaceEntry.heartbeat.contextMode);
-    return message == null
-      ? {
-          enabled: workspaceEntry.heartbeat.enabled,
-          intervalMs: workspaceEntry.heartbeat.intervalMs,
-          contextMode,
-        }
-      : {
-          enabled: workspaceEntry.heartbeat.enabled,
-          intervalMs: workspaceEntry.heartbeat.intervalMs,
-          message,
-          contextMode,
-        };
+    return {
+      enabled: workspaceEntry.heartbeat.enabled,
+      intervalMs: workspaceEntry.heartbeat.intervalMs,
+      contextMode,
+      ...(message != null ? { message } : {}),
+    };
   }
 
   async setHeartbeatSettings(
@@ -3356,26 +3325,18 @@ export class WorkspaceService extends EventEmitter {
       }
 
       const nextMessage = hasMessageUpdate
-        ? normalizeHeartbeatMessageInput(settings.message)
+        ? sanitizeHeartbeatMessage(settings.message)
         : sanitizeHeartbeatMessage(workspaceEntry.heartbeat?.message);
       const nextContextMode = hasContextModeUpdate
         ? sanitizeHeartbeatContextMode(settings.contextMode)
         : sanitizeHeartbeatContextMode(workspaceEntry.heartbeat?.contextMode);
-      const nextSettings: WorkspaceHeartbeatSettings =
-        nextMessage == null
-          ? {
-              enabled: settings.enabled,
-              // Keep the interval on disk even when disabled so re-enabling restores the user's choice.
-              intervalMs: settings.intervalMs,
-              contextMode: nextContextMode,
-            }
-          : {
-              enabled: settings.enabled,
-              // Keep the interval on disk even when disabled so re-enabling restores the user's choice.
-              intervalMs: settings.intervalMs,
-              message: nextMessage,
-              contextMode: nextContextMode,
-            };
+      // Keep the interval on disk even when disabled so re-enabling restores the user's choice.
+      const nextSettings: WorkspaceHeartbeatSettings = {
+        enabled: settings.enabled,
+        intervalMs: settings.intervalMs,
+        contextMode: nextContextMode,
+        ...(nextMessage != null ? { message: nextMessage } : {}),
+      };
 
       const changed =
         workspaceEntry.heartbeat?.enabled !== nextSettings.enabled ||
diff --git a/src/node/services/worktreeArchiveSnapshotService.ts b/src/node/services/worktreeArchiveSnapshotService.ts
index 2000a53b06..ccfcdbaa7d 100644
--- a/src/node/services/worktreeArchiveSnapshotService.ts
+++ b/src/node/services/worktreeArchiveSnapshotService.ts
@@ -291,38 +291,16 @@ export class WorktreeArchiveSnapshotService {
           const acknowledgedSet = new Set(args.acknowledgedUntrackedPaths);
           const newPaths = currentUntracked.filter((p) => !acknowledgedSet.has(p));
           if (newPaths.length > 0) {
-            const latestUntrackedResult = await this.getUnsupportedUntrackedPaths({
+            return this.buildUntrackedConfirmationErr({
               workspaceId: args.workspaceId,
               workspaceMetadata: args.workspaceMetadata,
             });
-            if (!latestUntrackedResult.success) {
-              return Err(latestUntrackedResult.error);
-            }
-            assert(
-              latestUntrackedResult.data.length > 0,
-              "captureSnapshotForArchive: expected current untracked paths when confirmation is required"
-            );
-            return Err({
-              kind: "confirm-lossy-untracked-files",
-              paths: latestUntrackedResult.data,
-            });
           }
         } else if (currentUntracked.length > 0) {
-          const latestUntrackedResult = await this.getUnsupportedUntrackedPaths({
+          return this.buildUntrackedConfirmationErr({
             workspaceId: args.workspaceId,
             workspaceMetadata: args.workspaceMetadata,
           });
-          if (!latestUntrackedResult.success) {
-            return Err(latestUntrackedResult.error);
-          }
-          assert(
-            latestUntrackedResult.data.length > 0,
-            "captureSnapshotForArchive: expected current untracked paths when confirmation is required"
-          );
-          return Err({
-            kind: "confirm-lossy-untracked-files",
-            paths: latestUntrackedResult.data,
-          });
         }
         await this.ensureNoDirtySubmodules(projectRepo.repoCwd);
 
@@ -680,6 +658,32 @@ export class WorktreeArchiveSnapshotService {
     return detectDefaultTrunkBranch(args.projectPath);
   }
 
+  /**
+   * Fetch the current untracked-file set for a workspace and return an
+   * `Err` asking the user to re-confirm. Used by `captureSnapshotForArchive`
+   * when untracked files are detected that the user hasn't acknowledged.
+   */
+  private async buildUntrackedConfirmationErr(args: {
+    workspaceId: string;
+    workspaceMetadata: WorkspaceMetadata;
+  }): Promise<Result<never, CaptureSnapshotForArchiveError>> {
+    const latestUntrackedResult = await this.getUnsupportedUntrackedPaths({
+      workspaceId: args.workspaceId,
+      workspaceMetadata: args.workspaceMetadata,
+    });
+    if (!latestUntrackedResult.success) {
+      return Err(latestUntrackedResult.error);
+    }
+    assert(
+      latestUntrackedResult.data.length > 0,
+      "captureSnapshotForArchive: expected current untracked paths when confirmation is required"
+    );
+    return Err({
+      kind: "confirm-lossy-untracked-files",
+      paths: latestUntrackedResult.data,
+    });
+  }
+
   /**
    * List untracked files/directories in a repo that archive snapshots cannot preserve.
    * Returns a sorted, normalized array of relative paths.
diff --git a/tests/ui/storybook/coverage.test.ts b/tests/ui/storybook/coverage.test.ts
index 1ca9c6a843..e2f7028def 100644
--- a/tests/ui/storybook/coverage.test.ts
+++ b/tests/ui/storybook/coverage.test.ts
@@ -24,7 +24,6 @@ const REQUIRED_COLOCATED_STORIES = [
 const MIGRATED_APP_STORIES = [
   "App.sidebar.stories.tsx",
   "App.welcome.stories.tsx",
-  "App.landingPage.stories.tsx",
   "App.errors.stories.tsx",
   "App.titlebar.stories.tsx",
   "App.projectCreate.stories.tsx",