Revert "Pass through the initial options on creation"

[bpasero]

Reverts #301598
Related: #301677

[Copilot]

Pull request overview

Reverts the earlier change that forwarded initial session options during chat session creation/initialization, removing the related context plumbing across the proposed API surface and the main thread/ext host bridge.

Changes:

• Removes session-option context from the proposed ChatSessionContentProvider.provideChatSessionContent signature and related DTOs.
• Removes initialSessionOptions propagation from internal new-session request types and the ext host/controller invocation path.
• Updates main thread initialization and tests to no longer pass/expect the initial session-options context.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.chatSessionsProvider.d.ts	Reverts proposed API additions for passing session options during session content resolution.
src/vs/workbench/contrib/chat/common/chatSessionsService.ts	Removes initialSessionOptions from the internal new-session request interface.
src/vs/workbench/contrib/chat/common/chatService/chatServiceImpl.ts	Stops including initial session options when creating a new session item for untitled remote sessions.
src/vs/workbench/api/test/browser/mainThreadChatSessions.test.ts	Removes test that asserted initial session options were forwarded during initialization.
src/vs/workbench/api/common/extHostChatSessions.ts	Removes context DTO usage and stops forwarding initial session options to extensions during session content resolution/new-item handler.
src/vs/workbench/api/common/extHost.protocol.ts	Removes the session-content context DTO and updates the $provideChatSessionContent shape signature accordingly.
src/vs/workbench/api/browser/mainThreadChatSessions.ts	Updates session initialization to call $provideChatSessionContent without the removed context argument.