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/routes/companies.py

@@ -45,13 +45,17 @@ def create_companies_router(
     )
 
     # Helper function to get companies - can be cached
-    async def _get_user_companies_data(username: str) -> List[Company]:
+    async def _get_user_companies_data(username: str, server_id: Optional[str] = None) -> List[Company]:
         """
         Get list of companies for a user from Oracle.
+
+        Args:
+            username: The username to get companies for
+            server_id: The Oracle server ID (for multi-server mode)
         """
         companies = []
 
-        async with oracle_pool.get_connection() as connection:
+        async with oracle_pool.get_connection(server_id) as connection:
             with connection.cursor() as cursor:
                 try:
                     # Get user ID
@@ -97,10 +101,11 @@ def create_companies_router(
         return companies
 
     # Apply cache decorator if provided
+    # Include server_id in cache key for multi-server mode
     if cache_decorator:
         _get_user_companies_data = cache_decorator(
             cache_type='companies',
-            key_params=['username']
+            key_params=['username', 'server_id']
         )(_get_user_companies_data)
 
     @router.get("", response_model=CompanyListResponse)
@@ -111,7 +116,9 @@ def create_companies_router(
     ):
         """Get list of companies the user has access to."""
         try:
-            companies = await _get_user_companies_data(current_user.username)
+            # Get server_id from request state (injected by auth middleware from JWT)
+            server_id = getattr(request.state, 'server_id', None)
+            companies = await _get_user_companies_data(current_user.username, server_id)
 
             return CompanyListResponse(
                 companies=companies,
@@ -124,6 +131,7 @@ def create_companies_router(
     @router.get("/{company_id}", response_model=Company)
     async def get_company_details(
         company_id: str,
+        request: Request,
         current_user: CurrentUser = Depends(get_current_user)
     ):
         """Get details of a specific company."""
@@ -132,7 +140,9 @@ def create_companies_router(
             raise HTTPException(403, f"Nu aveți acces la firma {company_id}")
 
         try:
-            async with oracle_pool.get_connection() as connection:
+            # Get server_id from request state (injected by auth middleware from JWT)
+            server_id = getattr(request.state, 'server_id', None)
+            async with oracle_pool.get_connection(server_id) as connection:
                 with connection.cursor() as cursor:
                     cursor.execute("""
                         SELECT ID_FIRMA, FIRMA, SCHEMA, COD_FISCAL