feat(sessions): implement user session management with session tracking and revocation

- Introduced new database schema for user sessions and session events.
- Implemented session management page with filtering, sorting, and revocation capabilities.
- Added backend services for creating, revoking, and expiring user sessions.
- Implemented session cookie handling and security measures.
- Created tests for session management functionalities and security features.

.env.example

@@ -29,9 +29,9 @@ NODE_ENV=development
 # Database (PostgreSQL)
 DATABASE_URL="postgresql://doktainer:doktainerdb@localhost:5432/doktainer?schema=public"
 
-# JWT settings
-JWT_SECRET=dev-super-secret-jwt-key-change-in-production-32chars
-JWT_EXPIRES_IN=7d
+# Absolute lifetime for database-backed login sessions. User settings control
+# the shorter sliding inactivity timeout.
+SESSION_ABSOLUTE_TIMEOUT_HOURS=168
 
 
 # /* -------------------------- Reverse proxy / rate limiting ------------------------- */