webui: Add MCP CORS Proxy detection logic & UI (#20167)
* refactor: MCP store cleanup
* feat: Add MCP proxy availability detection
* fix: Sidebar icon
* chore: update webui build output
* chore: Formatting
* chore: update webui build output
* chore: Update package lock
* chore: update webui build output
* chore: update webui build output
* chore: update webui build output
