fix: add projectPath to tauri-action for monorepo support

- Adds projectPath: apps/desktop to locate Tauri project in monorepo
- Fixes signature generation for updater artifacts (.sig files)
- Enables proper latest.json generation for auto-updates

Author: Mohammod Al Amin Ashik

.github/workflows/release.yml

@@ -123,6 +123,7 @@ jobs:
           APPLE_PASSWORD: ${{ secrets.APPLE_PASSWORD }}
           APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
         with:
+          projectPath: apps/desktop
           # Use tagName to find and upload to the existing release created by release-please
           tagName: ${{ needs.release-please.outputs.tag_name }}
           releaseName: 'McpMux v${{ needs.release-please.outputs.version }}'