Separate implementation of Copilot CLI, controller vs old API

[DonJayamanne]

No description provided.

[Copilot]

Pull request overview

This PR refactors the Copilot CLI chat sessions implementation to remove the ChatSessionItemController-based path and unify around the vscode.ChatSessionItemProvider flow, while also extracting a small provider interface for cross-component use.

Changes:

• Remove the ChatSessionItemController feature-flagged implementation and related “new session id” tracking.
• Introduce ICopilotCLIChatSessionItemProvider and update ChatSessionRepositoryTracker to depend on the interface instead of the concrete provider.
• Restructure ChatSessionsContrib initialization to register Copilot CLI services via a helper and reuse the metadata store for Claude sessions.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts	Removes controller path; simplifies refresh/swap handling; updates fork flow to always find items via the provider.
src/extension/chatSessions/vscode-node/copilotCLIChatSessions.ts	Adds ICopilotCLIChatSessionItemProvider interface (but also contains a large commented-out prior implementation).
src/extension/chatSessions/vscode-node/chatSessions.ts	Refactors registration: Copilot CLI services registered via helper; Claude sessions created using returned metadata store.
src/extension/chatSessions/vscode-node/chatSessionRepositoryTracker.ts	Switches dependency from concrete provider to ICopilotCLIChatSessionItemProvider and relies on refreshSession.

Comments suppressed due to low confidence (1)

src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts:212

• refreshSession ignores refreshOptions (and doesn’t distinguish update vs delete). At minimum, mark the parameter as intentionally unused (e.g., _refreshOptions) to satisfy unused-parameter checks; ideally handle reason:'delete' by cleaning up any per-session state and/or doing targeted refresh logic.

	public async refreshSession(refreshOptions: { reason: 'update'; sessionId: string } | { reason: 'delete'; sessionId: string }): Promise<void> {
		this._onDidChangeChatSessionItems.fire();
	}