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/invoice_service.py

@@ -5,7 +5,7 @@ Service pentru logica facturi - Portează query-urile din aplicația Flask
 import os
 
 from shared.database.oracle_pool import oracle_pool
-from typing import List, Tuple
+from typing import List, Tuple, Optional
 from ..models.invoice import Invoice, InvoiceFilter, InvoiceListResponse, InvoiceSummary
 from ..cache.decorators import cached
 from decimal import Decimal
@@ -17,10 +17,10 @@ class InvoiceService:
     """Service pentru gestionarea facturilor"""
 
     @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 PERMANENT)"""
-        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
@@ -36,15 +36,15 @@ class InvoiceService:
                 return schema_result[0]
 
     @staticmethod
-    @cached(cache_type='invoices', key_params=['filter_params', 'username'])
-    async def get_invoices(filter_params: InvoiceFilter, username: str) -> InvoiceListResponse:
+    @cached(cache_type='invoices', key_params=['filter_params', 'username', 'server_id'])
+    async def get_invoices(filter_params: InvoiceFilter, username: str, server_id: Optional[str] = None) -> InvoiceListResponse:
         """
         Obține lista de facturi - Query simplu pentru afișare în tabel (CACHED 10 min)
         """
         company_id = int(filter_params.company)
-        schema = await InvoiceService._get_schema(company_id)
+        schema = await InvoiceService._get_schema(company_id, server_id)
 
-        async with oracle_pool.get_connection() as connection:
+        async with oracle_pool.get_connection(server_id) as connection:
             with connection.cursor() as cursor:
                 
                 # Determină conturile în funcție de partner_type
@@ -240,11 +240,11 @@ class InvoiceService:
                 )
     
     @staticmethod
-    async def get_invoice_details(company: str, invoice_number: str, username: str) -> Invoice:
+    async def get_invoice_details(company: str, invoice_number: str, username: str, server_id: Optional[str] = None) -> Invoice:
         """
         Obține detaliile unei facturi specifice
         """
-        async with oracle_pool.get_connection() as connection:
+        async with oracle_pool.get_connection(server_id) as connection:
             with connection.cursor() as cursor:
                 # Obține schema din v_nom_firme bazat pe id_firma
                 company_id = int(company)