feat(mdviewer): forward unhandled keyboard shortcuts to Phoenix keybinding manager

Modifier shortcuts not handled by the md editor (bold, italic, undo, etc.)
are forwarded to Phoenix via postMessage so keybindings like Ctrl+S,
Ctrl+Shift+F, etc. work while editing markdown. Events dispatched on
document.body where KeyBindingManager listens.

Also adds to-create-tests.md with integration test checklist.

Author: abose

src-mdviewer/src/bridge.js

@@ -150,6 +150,10 @@ export function initBridge() {
 
     // Intercept keyboard shortcuts in capture phase before the mdviewr editor handles them.
     // Undo/redo is routed through CM5's undo stack so both editors stay in sync.
+    // Unhandled modifier shortcuts are forwarded to Phoenix's keybinding manager.
+    const _mdEditorHandledKeys = new Set(["b", "i", "k", "u", "z", "y", "a", "c", "v", "x"]); // Ctrl/Cmd + key
+    const _mdEditorHandledShiftKeys = new Set(["x", "X", "z"]); // Ctrl/Cmd + Shift + key
+
     document.addEventListener("keydown", (e) => {
         if (e.key === "Escape") {
             sendToParent("embeddedEscapeKeyPressed", {});
@@ -170,6 +174,26 @@ export function initBridge() {
             e.preventDefault();
             e.stopImmediatePropagation();
             sendToParent("mdviewrRedo", {});
+            return;
+        }
+
+        // Forward unhandled modifier shortcuts to Phoenix keybinding manager
+        if (getState().editMode) {
+            const isHandled = e.shiftKey
+                ? _mdEditorHandledShiftKeys.has(e.key)
+                : _mdEditorHandledKeys.has(e.key);
+            if (!isHandled) {
+                e.preventDefault();
+                e.stopImmediatePropagation();
+                sendToParent("mdviewrKeyboardShortcut", {
+                    key: e.key,
+                    code: e.code,
+                    ctrlKey: e.ctrlKey,
+                    metaKey: e.metaKey,
+                    shiftKey: e.shiftKey,
+                    altKey: e.altKey
+                });
+            }
         }
     }, true);
 

src-mdviewer/to-create-tests.md

@@ -0,0 +1,92 @@
+# Markdown Viewer/Editor — Integration Tests To Create
+
+## Keyboard Shortcut Forwarding
+- [ ] Ctrl+S in edit mode triggers Phoenix save (not consumed by md editor)
+- [ ] Ctrl+P in edit mode opens Quick Open
+- [ ] Ctrl+Shift+F in edit mode opens Find in Files
+- [ ] Ctrl+B/I/U in edit mode applies bold/italic/underline (not forwarded)
+- [ ] Ctrl+K in edit mode opens link input (not forwarded)
+- [ ] Ctrl+Shift+X in edit mode applies strikethrough (not forwarded)
+- [ ] Ctrl+Z/Y in edit mode triggers undo/redo via CM (routed through Phoenix undo stack)
+- [ ] Ctrl+A/C/V/X in edit mode work natively (select all, copy, paste, cut)
+- [ ] Escape in edit mode sends focus back to Phoenix editor
+- [ ] F-key shortcuts (e.g. F8 for live preview toggle) work in edit mode
+
+## Document Cache & File Switching
+- [ ] Switching between two MD files is instant (no re-render, DOM cached)
+- [ ] Scroll position preserved per-document on switch
+- [ ] Edit/reader mode preserved globally across file switches
+- [ ] Switching MD → HTML → MD reuses persistent md iframe (no reload)
+- [ ] Closing live preview panel and reopening preserves md iframe and cache
+- [ ] Project switch clears all cached documents
+- [ ] Working set changes sync to iframe (files removed from working set go to LRU)
+- [ ] LRU cache evicts beyond 20 non-working-set files
+- [ ] Reload button (in LP toolbar) re-renders current file, preserves scroll and edit mode
+
+## Selection Sync (Bidirectional)
+- [ ] Selecting text in CM highlights corresponding block in md viewer
+- [ ] Selecting text in md viewer selects corresponding text in CM
+- [ ] Clicking in md viewer (no selection) clears CM selection
+- [ ] Clicking in CM clears md viewer highlight
+- [ ] Selection sync respects cursor sync toggle (disabled when sync off)
+
+## Cursor/Scroll Sync
+- [ ] Clicking in CM scrolls md viewer to corresponding element
+- [ ] Clicking in md viewer scrolls CM to corresponding line (centered)
+- [ ] Cursor sync toggle button disables/enables bidirectional sync
+- [ ] Cursor sync toggle state preserved across toolbar re-renders (file switch, mode toggle)
+- [ ] Content sync still works when cursor sync is disabled
+
+## Edit Mode & Entitlement Gating
+- [ ] Free user sees Edit button → clicking shows upsell dialog
+- [ ] Pro user sees Edit button → clicking enters edit mode
+- [ ] Entitlement change (free→pro) switches to edit mode automatically
+- [ ] Entitlement change (pro→free) switches to reader mode automatically
+- [ ] Edit/Reader toggle works correctly in the iframe toolbar
+
+## Toolbar & UI
+- [ ] Phoenix play button and mode dropdown hidden for MD files
+- [ ] Phoenix play button and mode dropdown visible for HTML files
+- [ ] Phoenix play button and mode dropdown visible for custom server MD files
+- [ ] Progressive toolbar collapse: blocks collapse first, then lists, then text formatting
+- [ ] Toolbar collapse thresholds work at various widths
+- [ ] Dropdown menus in collapsed toolbar open and close correctly
+- [ ] Format buttons apply formatting and close dropdown
+- [ ] Tooltip delay is 800ms (not too aggressive)
+- [ ] Underline button has shortcut in tooltip (Ctrl+U / ⌘U)
+- [ ] Reader button has book-open icon and "Switch to reader mode" title
+- [ ] Edit button has pencil icon and "Switch to edit mode" title
+- [ ] 1px white line at bottom of preview not visible (box-sizing: border-box on toolbar)
+
+## Checkbox (Task List) Sync
+- [ ] Clicking checkbox in edit mode toggles it and syncs to CM source ([x] ↔ [ ])
+- [ ] Checkboxes enabled in edit mode, disabled in reader mode
+- [ ] Checkbox toggle creates an undo entry
+- [ ] Undo reverses checkbox toggle
+
+## Format Bar & Link Popover
+- [ ] Format bar appears on text selection (single line, not wrapping)
+- [ ] Format bar includes underline button
+- [ ] Format bar dismissed on scroll
+- [ ] Link popover appears when clicking a link in edit mode
+- [ ] Link popover URL opens in default browser (not Electron window)
+- [ ] Link popover dismissed on scroll
+
+## Scroll Behavior
+- [ ] Cursor sync scroll is instant (not smooth animated)
+- [ ] Scroll restore on file switch uses exact pixel position (no jump)
+- [ ] Scroll restore on reload uses source-line-based positioning
+- [ ] No progressive scroll-down on reload with many images (source-line approach)
+
+## Border & Styling
+- [ ] Subtle bottom border on #mainNavBar (rgba(255,255,255,0.08))
+- [ ] Subtle bottom border on #live-preview-plugin-toolbar (rgba(255,255,255,0.08))
+- [ ] No medium-zoom magnifying glass cursor on images
+- [ ] Cursor sync icon is subtle (secondary text color, not accent blue)
+
+## Translation (i18n)
+- [ ] en.json strings load correctly (toolbar.reader, format.underline, etc.)
+- [ ] Locale with region code (e.g. en-GB) falls back to base (en) if specific file missing
+- [ ] No "Failed to load locale" console warnings for valid locales
+- [ ] gulp translateStrings translates both Phoenix NLS and mdviewer locales
+- [ ] Translated locale files copied back to src-mdviewer/src/locales/

src/extensionsIntegrated/Phoenix-live-preview/MarkdownSync.js

@@ -114,6 +114,9 @@ define(function (require, exports, module) {
             case "mdviewrCursorSyncToggle":
                 _cursorSyncEnabled = !!data.enabled;
                 break;
+            case "mdviewrKeyboardShortcut":
+                _forwardKeyboardShortcut(data);
+                break;
             case "embeddedIframeFocusEditor":
                 if (data.sourceLine != null) {
                     _scrollCMToLine(data.sourceLine);
@@ -595,6 +598,27 @@ define(function (require, exports, module) {
         _syncingFromIframe = false;
     }
 
+    // --- Keyboard shortcut forwarding ---
+
+    /**
+     * Forward an unhandled keyboard shortcut from the mdviewer iframe to Phoenix's
+     * keybinding manager by dispatching a synthetic KeyboardEvent on the document.
+     */
+    function _forwardKeyboardShortcut(data) {
+        const event = new KeyboardEvent("keydown", {
+            key: data.key,
+            code: data.code,
+            ctrlKey: data.ctrlKey,
+            metaKey: data.metaKey,
+            shiftKey: data.shiftKey,
+            altKey: data.altKey,
+            bubbles: true,
+            cancelable: true
+        });
+        // KeyBindingManager listens on document.body, not document
+        document.body.dispatchEvent(event);
+    }
+
     // --- Helpers ---
 
     function _getIframeWindow() {