- Removed the `generate_pkce_pair` function from `airtable_add_connector_route.py` and relocated it to `oauth_security.py` for better organization.
- Updated imports in `airtable_add_connector_route.py` to reflect the new location of the PKCE generation function.
- Added `generate_code_verifier` function to create a PKCE code verifier for enhanced security.
- Updated Google Calendar, Drive, and Gmail connector routes to utilize the PKCE code verifier during OAuth authorization.
- Modified state management to include the code verifier for secure state generation and validation.
- Added encryption for sensitive tokens (access token, refresh token, client secret) in Google Calendar, Google Drive, Gmail, Linear, and Notion connectors to enhance security.
- Introduced OAuthStateManager for secure state parameter generation and validation, improving the integrity of OAuth flows.
- Updated callback routes to handle state validation and error management, ensuring robust handling of authorization processes.
- Enhanced indexers to support decryption of tokens for backward compatibility, maintaining functionality with existing encrypted credentials.
- Improved validation for date parameters in connector routes to ensure proper input handling.
