[FEATURE]: Add V2 project metadata update API

Feature hasn't been suggested before.

• I searched existing issues and did not find an issue requesting this V2 API.

Describe the enhancement you want to request

The V2 project API currently supports listing projects and resolving the current project, but it cannot update metadata already stored on Project.Info, such as the project name, icon, color, or startup command.

This leaves project editing unavailable to V2 clients after the V1 compatibility API was removed.

I propose adding:

• PATCH /api/project/:projectID
• Optional name, icon, and commands fields
• Omitted fields preserved and empty strings treated as clearing a value
• The complete updated Project.Info returned
• A typed 404 response for unknown projects
• A public ephemeral project.updated event containing the complete project

The project database and schema already contain these metadata fields. Client UI integration can remain separate from the API change.

Related prior API work: #38443
Current implementation: #42904