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>

backend/modules/reports/routers/trial_balance.py

@@ -2,7 +2,7 @@
 API Router for Trial Balance (Balanță de Verificare)
 Refactored to use service layer with caching
 """
-from fastapi import APIRouter, Depends, HTTPException, Query
+from fastapi import APIRouter, Depends, HTTPException, Query, Request
 from typing import Optional
 from datetime import date
 # import sys  # Removed - no longer needed
@@ -20,6 +20,7 @@ router = APIRouter()
 
 @router.get("/", response_model=TrialBalanceResponse)
 async def get_trial_balance(
+    request: Request,
     company: str = Query(description="Codul firmei (ID)"),
     luna: Optional[int] = Query(None, ge=1, le=12, description="Luna (1-12), default: luna curentă"),
     an: Optional[int] = Query(None, ge=2000, le=2100, description="An, default: anul curent"),
@@ -48,6 +49,8 @@ async def get_trial_balance(
                 detail=f"Nu aveți acces la firma {company}"
             )
 
+        server_id = getattr(request.state, 'server_id', None)
+
         # Setează valorile implicite pentru lună și an (luna și anul curent)
         current_date = date.today()
         if luna is None:
@@ -69,7 +72,8 @@ async def get_trial_balance(
             sort_order=sort_order,
             page=page,
             page_size=page_size,
-            username=current_user.username
+            username=current_user.username,
+            server_id=server_id
         )
 
         return TrialBalanceResponse(