Add onDidDispose event for chat sessions input states

[mjbvz]

No description provided.

[Copilot]

Pull request overview

Adds a disposal lifecycle hook to chat session input states so extensions can react when an input state is no longer valid.

Changes:

• Introduce ChatSessionInputState.onDidDispose in the proposed API.
• Implement onDidDispose in ChatSessionInputStateImpl and dispose input states when sessions/controllers are disposed.
• Add logic to dispose prior input states associated with a session resource.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.chatSessionsProvider.d.ts	Adds onDidDispose to the proposed ChatSessionInputState API surface.
src/vs/workbench/api/common/extHostChatSessions.ts	Implements the new event and wires disposal of input states to session/controller lifecycle paths.

Copilot's findings

• Files reviewed: 1/2 changed files
• Comments generated: 1

[Copilot]

Disposing prior input states here (inside getInputStateForSession, which is used by the option-group proxy command wrapper) can dispose the active ChatSessionInputStateImpl that the UI/extension is still using to receive onDidChange updates for the session. This call path is triggered when a user runs an option-group command and should not tear down the session’s live input state. Suggest removing the _disposeInputStatesForResource(...) call from this method (or changing the command wrapper to use an untracked/snapshot input state) and only disposing/replacing states in the session lifecycle paths ($provideChatSessionContent / $provideChatSessionInputState / $disposeChatSessionContent).

Suggested change

	// Dispose any previous input states for this session resource
	if (sessionResource && controllerData) {
	this._disposeInputStatesForResource(controllerData.inputStates, sessionResource);
	}