Add authentication, user management, and database migration features

- Implement OAuth 2.0 and PAT authentication methods
- Add user management, roles, and profile functionality
- Add database migrations and admin user scripts
- Update services for authentication and user settings
- Add protected routes and permission hooks
- Update documentation for authentication and database access

CLAUDE.md

@@ -193,9 +193,9 @@ JIRA_ATTR_APPLICATION_CLUSTER=<attr_id>
 JIRA_ATTR_APPLICATION_TYPE=<attr_id>
 
 # AI Classification
-ANTHROPIC_API_KEY=<claude_api_key>
-OPENAI_API_KEY=<openai_api_key>         # Optional: alternative to Claude
-DEFAULT_AI_PROVIDER=claude              # 'claude' or 'openai'
+# Note: AI API keys (ANTHROPIC_API_KEY, OPENAI_API_KEY, TAVILY_API_KEY),
+# default AI provider, and web search are configured per-user in profile settings,
+# not in environment variables
 
 # Server
 PORT=3001