feat: integrate tauri-plugin-oauth for enhanced OAuth support

- Added tauri-plugin-oauth dependency to Cargo.toml for OAuth functionality.
- Updated default.json capabilities to include OAuth permissions.
- Implemented OAuth server start command in lib.rs to handle OAuth flow.
- Enhanced signInWithProvider function in supabase.js to support Tauri OAuth flow, including error handling and event listening for OAuth callbacks.
- Minor formatting fix in theme-loader.js for consistency.

Author: murdercode