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/services/trial_balance_service.py

@@ -4,9 +4,9 @@ Refactored to use caching system for optimal performance
 """
 # import sys  # Removed - no longer needed
 import os
+from typing import Dict, Any, Optional
 
 from shared.database.oracle_pool import oracle_pool
-from typing import Dict, Any
 from ..models.trial_balance import (
     TrialBalanceItem,
     TrialBalanceFilters,
@@ -25,14 +25,14 @@ class TrialBalanceService:
     """Service pentru gestionarea balanței de verificare cu cache"""
 
     @staticmethod
-    @cached(cache_type='schema', key_params=['company_id'])
-    async def _get_schema(company_id: int) -> str:
+    @cached(cache_type='schema', key_params=['company_id', 'server_id'])
+    async def _get_schema(company_id: int, server_id: Optional[str] = None) -> str:
         """
         Obține schema pentru company_id (CACHED 24h)
 
         This is cached permanently because company schemas rarely change.
         """
-        async with oracle_pool.get_connection() as connection:
+        async with oracle_pool.get_connection(server_id) as connection:
             with connection.cursor() as cursor:
                 schema_query = """
                     SELECT schema
@@ -50,7 +50,7 @@ class TrialBalanceService:
     @staticmethod
     @cached(cache_type='trial_balance', key_params=['company_id', 'luna', 'an', 'cont_filter',
                                                       'denumire_filter', 'sort_by', 'sort_order',
-                                                      'page', 'page_size', 'username'])
+                                                      'page', 'page_size', 'username', 'server_id'])
     async def get_trial_balance(
         company_id: int,
         luna: int,
@@ -61,7 +61,8 @@ class TrialBalanceService:
         sort_order: str,
         page: int,
         page_size: int,
-        username: str
+        username: str,
+        server_id: Optional[str] = None
     ) -> Dict[str, Any]:
         """
         Obține balanța de verificare sintetică (CACHED 10 min)
@@ -80,12 +81,13 @@ class TrialBalanceService:
             page: Pagina
             page_size: Mărimea paginii
             username: Username pentru cache tracking
+            server_id: Optional Oracle server identifier for multi-server support
 
         Returns:
             Dictionary cu items, pagination, filters_applied
         """
         # Get schema (cached separately)
-        schema = await TrialBalanceService._get_schema(company_id)
+        schema = await TrialBalanceService._get_schema(company_id, server_id)
 
         # Validate sort_order
         if sort_order.lower() not in ['asc', 'desc']:
@@ -97,7 +99,7 @@ class TrialBalanceService:
         if sort_by.upper() not in valid_sort_columns:
             sort_by = 'CONT'
 
-        async with oracle_pool.get_connection() as connection:
+        async with oracle_pool.get_connection(server_id) as connection:
             with connection.cursor() as cursor:
                 # Build base query for VBAL VIEW
                 base_query = f"""