Add chat model reference inspection

[roblourens]

Summary

• add a developer command to inspect live chat model references, holders, and pending-disposal state
• thread debug owner labels through chat session acquisition paths so the inspection output shows who created or is retaining each model
• attribute startup-revived pending-edit sessions and modified-edit self-retention so stale edit-backed models are easier to diagnose

Validation

• VS Code build watch stayed clean for the touched files
• npm run compile-check-ts-native
• focused tests passed for chatModelStore.test.ts and the new modified-edits keep-alive assertion in chatService.test.ts
• running the compiled chatService.test.ts file also hit an existing unrelated failure in retrieveSession (0 !== 2), so the focused validation was used instead
• node --experimental-strip-types build/hygiene.ts ... on the changed files

(Written by Copilot)

[Copilot]

Pull request overview

Adds new developer-facing diagnostics to inspect live chat model references and track who created/retains each model, to help debug leaks and “pending disposal” cases across chat/session acquisition paths.

Changes:

• Introduces reference-owner + creation-owner tracking in ChatModelStore and exposes a debug snapshot API.
• Threads a debugOwner label through IChatService session acquisition/loading APIs and key call sites.
• Adds a new developer command to render a Markdown inspection report for live chat model references, plus focused tests for the new tracking/keep-alive behavior.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/vs/workbench/contrib/chat/common/model/chatModelStore.ts	Tracks reference holders/creation owner and exposes a debug snapshot of live models/references.
src/vs/workbench/contrib/chat/common/chatService/chatService.ts	Extends IChatService API with debug-owner threading and a new debug snapshot accessor.
src/vs/workbench/contrib/chat/common/chatService/chatServiceImpl.ts	Implements debug-owner plumbing and surfaces model reference debug snapshot from the model store.
src/vs/workbench/contrib/chat/common/model/chatModel.ts	Adds debug-owner labels for self-reference keep-alive holders.
src/vs/workbench/contrib/chat/browser/actions/chatDeveloperActions.ts	Adds “Inspect Chat Model References” developer command outputting a Markdown report.
src/vs/workbench/contrib/chat/browser/widgetHosts/viewPane/chatViewPane.ts	Passes debug-owner labels through session load/restore paths.
src/vs/workbench/contrib/chat/browser/widgetHosts/editor/chatEditorInput.ts	Passes debug-owner labels when resolving/loading/creating sessions.
src/vs/workbench/contrib/chat/browser/widgetHosts/chatQuick.ts	Passes debug-owner label when creating quick chat sessions.
src/vs/workbench/contrib/chat/browser/chatSessions/chatSessions.contribution.ts	Passes debug-owner label when sending prompts via sessions contribution.
src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionHoverWidget.ts	Passes debug-owner label when loading model for hover UI.
src/vs/workbench/contrib/chat/browser/actions/chatImportExport.ts	Passes debug-owner label for “import session” path.
src/vs/workbench/contrib/chat/browser/actions/chatForkActions.ts	Passes debug-owner label for fork-from-data paths.
src/vs/workbench/contrib/chat/test/common/model/chatModelStore.test.ts	Adds tests validating holder/creator tracking + pending-disposal-without-holders reporting.
src/vs/workbench/contrib/chat/test/common/chatService/chatService.test.ts	Adds test asserting modified-edits keep-alive holder attribution.
src/vs/workbench/contrib/chat/test/common/chatService/mockChatService.ts	Updates mock to satisfy new IChatService API surface.