feat: add Linear OAuth integration and connector routes

- Introduced Linear OAuth support with new environment variables for client ID, client secret, and redirect URI.
- Implemented Linear connector routes for OAuth flow, including authorization and callback handling.
- Updated existing components to accommodate Linear integration, including validation changes and connector configuration.
- Enhanced the Linear indexer to utilize OAuth access tokens instead of API keys.
- Adjusted UI components to reflect the new Linear connector without requiring special configuration.

surfsense_backend/.env.example

@@ -39,16 +39,21 @@ GOOGLE_CALENDAR_REDIRECT_URI=http://localhost:8000/api/v1/auth/google/calendar/c
 GOOGLE_GMAIL_REDIRECT_URI=http://localhost:8000/api/v1/auth/google/gmail/connector/callback
 GOOGLE_DRIVE_REDIRECT_URI=http://localhost:8000/api/v1/auth/google/drive/connector/callback
 
-# Notion OAuth for Notion Connector
-NOTION_CLIENT_ID=your_notion_client_id
-NOTION_CLIENT_SECRET=your_notion_client_secret
-NOTION_REDIRECT_URI=http://localhost:8000/api/v1/auth/notion/connector/callback
-
-# Airtable OAuth for Aitable Connector
+# OAuth for Aitable Connector
 AIRTABLE_CLIENT_ID=your_airtable_client_id
 AIRTABLE_CLIENT_SECRET=your_airtable_client_secret
 AIRTABLE_REDIRECT_URI=http://localhost:8000/api/v1/auth/airtable/connector/callback
 
+# OAuth for Linear Connector
+LINEAR_CLIENT_ID=your_linear_client_id
+LINEAR_CLIENT_SECRET=your_linear_client_secret
+LINEAR_REDIRECT_URI=http://localhost:8000/api/v1/auth/linear/connector/callback
+
+# OAuth for Notion Connector
+NOTION_CLIENT_ID=your_notion_client_id
+NOTION_CLIENT_SECRET=your_notion_client_secret
+NOTION_REDIRECT_URI=http://localhost:8000/api/v1/auth/notion/connector/callback
+
 # Embedding Model
 # Examples:
 #     # Get sentence transformers embeddings