Remove now unused ChatSessionChangedFile interface" (#308701)

[mjbvz]

Reapplying this now that our d.ts files are in sync

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Removes the ChatSessionChangedFile2 proposed API type and consolidates callers to use ChatSessionChangedFile for reporting changed files in chat session statistics.

Changes:

• Updates proposed d.ts to remove the ChatSessionChangedFile2 type and narrow changes to ChatSessionChangedFile[]
• Removes ChatSessionChangedFile2 from the ext host API surface and types
• Updates Copilot chat session providers/worktree service to instantiate and return ChatSessionChangedFile

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.chatSessionsProvider.d.ts	Drops ChatSessionChangedFile2 and narrows changes to ChatSessionChangedFile[].
src/vs/workbench/api/common/extHostTypes.ts	Removes ChatSessionChangedFile2 class and repurposes ChatSessionChangedFile constructor/signature.
src/vs/workbench/api/common/extHost.api.impl.ts	Stops exporting ChatSessionChangedFile2 from the API factory.
extensions/copilot/src/extension/chatSessions/vscode-node/copilotCloudSessionsProvider.ts	Switches instantiation from ChatSessionChangedFile2 to ChatSessionChangedFile.
extensions/copilot/src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts	Updates array types and instantiation to ChatSessionChangedFile.
extensions/copilot/src/extension/chatSessions/vscode-node/copilotCLIChatSessions.ts	Updates return type and instantiation to ChatSessionChangedFile.
extensions/copilot/src/extension/chatSessions/vscode-node/chatSessionWorktreeServiceImpl.ts	Updates worktree changes return types and constructors to ChatSessionChangedFile.
extensions/copilot/src/extension/chatSessions/common/chatSessionWorktreeService.ts	Updates interface return type to ChatSessionChangedFile[].

Copilot's findings

• Files reviewed: 7/8 changed files
• Comments generated: 2