T412023 - Oauth implementation

Add OAuth Authentication for Wikidata Editing Implements OAuth 1.0a authentication with Wikimedia to enable users to login and prepare for future Wikidata editing features (adding/editing authors and works).

Changes

• Authentication & Authorization
• OAuth 1.0a Integration
• Implemented OAuth flow using mwoauth library
• Added login route (/auth/login) to initiate OAuth handshake
• Added callback route (/oauth-callback) to handle Wikimedia redirects
• Added logout route (/auth/logout) to clear user session
• Session-based token storage (access tokens stored securely in Flask session)
• User Session Management
• Store Wikimedia username and user ID in session after successful authentication
• Persist session across page navigation
• Clear all OAuth data on logout
• Updated new translatable strings
• Updated Config-sample.py with new token fields required for Oauth
• Updated README.md with OAuth configuration section on how to test and work with Oauth Login flow locally.
• Added new dependencies to requirements.txt: mwoauth and flask-limiter

User Interface

• Added login button for unauthenticated users
• Added user dropdown for authenticated users showing: -Username with profile icon -Logout option
• Created oauth-callback.html template: -Shows loading spinner and "Authenticating with Wikimedia..." message -Provides user feedback during OAuth handshake

Rate Limiting

• Implemented Flask-Limiter
• Global rate limits: 200 requests/day, 50 requests/hour
• Login endpoint: 5 attempts/minute
• User-specific tracking: Uses Wikimedia user ID when authenticated, IP address when not
• Rate Limiting Configuration - Uses in-memory for development
• Rate Limit Error Handling