- Implemented OAuth 2.0 Authorization Server endpoints per RFCs, including token, introspection, revocation, and metadata discovery.
- Added user consent submission, listing, and revocation APIs alongside frontend integration for improved UX.
- Enforced stricter OAuth security measures (PKCE, state validation, scopes).
- Refactored schemas and services for consistency and expanded coverage of OAuth workflows.
- Updated documentation and type definitions for new API behaviors.
- Added models for `OAuthClient`, `OAuthState`, and `OAuthAccount`.
- Created Pydantic schemas to support OAuth flows, client management, and linked accounts.
- Implemented skeleton endpoints for OAuth Provider mode: authorization, token, and revocation.
- Updated router imports to include new `/oauth` and `/oauth/provider` routes.
- Added Alembic migration script to create OAuth-related database tables.
- Enhanced `users` table to allow OAuth-only accounts by making `password_hash` nullable.
