Sessions - simplify workspace tracking

[lszomoru]

No description provided.

[Copilot]

Pull request overview

This PR simplifies Copilot CLI session workspace/repository tracking by centralizing repository-change tracking in ChatSessionRepositoryTracker (rather than per-session request handling) and by serializing git repository resolution to avoid concurrent open/get races.

Changes:

• Serialize IGitService.getRepository* resolution behind a Sequencer and factor shared logic into a private _getRepository.
• Remove ChatSessionRepositoryTracker injection/usage from CopilotCLIChatSessionParticipant and update unit tests accordingly.
• Refactor ChatSessionRepositoryTracker to react to workspace-folder add/remove events and refresh session items when repository state changes.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/platform/git/vscode-node/gitServiceImpl.ts	Adds a Sequencer and consolidates repository lookup/open logic into _getRepository.
src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts	Removes per-request repository tracking hookup from the participant.
src/extension/chatSessions/vscode-node/chatSessions.ts	Stops passing the tracker into the participant; registers the tracker as a disposable service instance.
src/extension/chatSessions/vscode-node/chatSessionRepositoryTracker.ts	Moves tracking to workspace-folder change events and makes tracking methods private.
src/extension/chatSessions/vscode-node/test/copilotCLIChatSessionParticipant.spec.ts	Updates tests for the participant constructor signature and removes tracker mocking.

Comments suppressed due to low confidence (1)

src/extension/chatSessions/vscode-node/chatSessionRepositoryTracker.ts:84

• Within trackRepositoryChanges, the repository listener that gets registered on the new tracker uses an async callback (worktreeRepositoryState.onDidChange(async () => …)). Since the event source won’t await it, any thrown error can become an unhandled rejection. When setting up/replacing trackers, please ensure the listener body catches/logs failures (e.g. fire-and-forget with .catch(...)) so repository refresh failures don’t destabilize the extension host.

		if (this.trackers.has(worktreePath)) {
			const trackedRepositoryState = this.trackerRepositoryStates.get(worktreePath);

			// If the repository state is the same as the one we are already tracking,
			// do nothing. But if a new repository state is detected, which can happen
			// when the repository is reopened, we need to replace the tracker.
			if (trackedRepositoryState === worktreeRepositoryState) {
				this.logService.trace(`[ChatSessionRepositoryTracker][trackRepositoryChanges] Already tracking repository changes for session ${sessionId} and worktree ${worktreePath}.`);
				return;