feat: multi-Oracle server support with runtime switching

Complete implementation of multi-server Oracle database support:

Backend:
- Multi-pool Oracle with lazy loading per server
- Email-to-server cache for automatic server discovery
- JWT tokens include server_id claim
- /auth/check-identity and /auth/check-email endpoints
- /auth/my-servers endpoint for listing user's accessible servers
- Server switch with password re-authentication

Frontend:
- New ServerSelector component for header dropdown
- Multi-step login flow (identity → server → password)
- Server switching from header with password modal
- Mobile drawer menu with server selection
- Dark mode support for all new components
- URL bookmark support with ?server= query param

Scripts:
- Unified start.sh replacing start-prod.sh/start-test.sh
- Unified ssh-tunnel.sh with multi-server support
- Updated status.sh for new architecture

Tests:
- E2E tests for multi-server and single-server login flows
- Backend unit tests for all new endpoints
- Oracle multi-pool integration tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

shared/auth/middleware.py

@@ -310,8 +310,10 @@ class AuthenticationMiddleware(BaseHTTPMiddleware):
             request.state.user = current_user
             request.state.is_authenticated = True
             request.state.token_data = token_data
-            
-            logger.debug(f"User {current_user.username} authenticated successfully for path {path}")
+            # Extrage server_id din token pentru a fi folosit în query-uri Oracle
+            request.state.server_id = token_data.server_id
+
+            logger.debug(f"User {current_user.username} authenticated successfully for path {path} (server: {token_data.server_id or 'default'})")
             
         except Exception as e:
             logger.error(f"Error creating current user: {str(e)}")