Add source control panel and Windows-only release flow

[badcuban]

Summary

• Adds a new source control checkpoint panel in the web app with live refresh while it stays open.
• Scopes GitHub PR commands to the active repository context to avoid acting on the wrong repo.
• Refactors git/workspace source control plumbing to support the new panel and status caching.
• Switches release automation to a Windows-only GitHub Actions workflow that builds and publishes the Windows installer.
• Rebrands the app from T3 Code to BadCode across desktop/web assets, package metadata, and release naming.

Testing

• Not run (PR content only).
• Existing coverage was updated across desktop, server, and web source control paths.
• Release workflow changes were not executed locally.