feat: Add A-Z filter for clients/suppliers in Telegram bot

- Add A-Z alphabetical filter keyboard for clients and suppliers lists
  (same pattern as company selection, without emoji)
- Increase clients/suppliers list pagination from 10 to 20 items per page
- Remove emoji from company A-Z filter button for consistency
- Add 6 new callback handlers: clients_alpha_menu, clients_alpha:LETTER,
  clients_alpha_page:PAGE:LETTER, and supplier equivalents
- Dashboard service and models updates
- Telegram bot: email handlers, auth, DB operations, internal API improvements
- Frontend: dashboard cards updates (CashFlow, Clienti, Furnizori, Treasury)
- Frontend: SolduriCompactCard and CollapsibleCard improvements
- DashboardView enhancements
- start.sh and run-with-restart.sh script updates
- IIS web.config and service worker updates

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/modules/telegram/api/client.py

@@ -105,7 +105,8 @@ class BackendAPIClient:
     async def verify_user(
         self,
         oracle_username: str,
-        linking_code: str
+        linking_code: str,
+        server_id: Optional[str] = None
     ) -> Optional[Dict[str, Any]]:
         """
         Verify user exists in Oracle and get JWT token.
@@ -139,7 +140,8 @@ class BackendAPIClient:
                 "/api/telegram/auth/verify-user",
                 json={
                     "linking_code": linking_code,
-                    "oracle_username": oracle_username
+                    "oracle_username": oracle_username,
+                    "server_id": server_id
                 }
             )
 
@@ -185,12 +187,13 @@ class BackendAPIClient:
             logger.error(f"Failed to refresh token: {e}")
             return None
 
-    async def verify_email(self, email: str) -> dict:
+    async def verify_email(self, email: str, server_id: Optional[str] = None) -> dict:
         """
         Verify if email exists in Oracle database
 
         Args:
             email: Email address to verify
+            server_id: Optional Oracle server ID (for multi-server mode)
 
         Returns:
             dict with 'success' (bool), 'username' (str or None), and 'message' (str)
@@ -204,7 +207,7 @@ class BackendAPIClient:
 
             response = await self.client.post(
                 "/api/telegram/auth/verify-email",
-                json={"email": email}
+                json={"email": email, "server_id": server_id}
             )
             response.raise_for_status()
             return response.json()
@@ -229,7 +232,8 @@ class BackendAPIClient:
         email: str,
         password: str,
         telegram_user_id: int,
-        session_token: str
+        session_token: str,
+        server_id: Optional[str] = None
     ) -> dict:
         """
         Login via email + password with session token
@@ -239,6 +243,7 @@ class BackendAPIClient:
             password: Oracle password
             telegram_user_id: Telegram user ID
             session_token: Signed token from code validation
+            server_id: Optional Oracle server ID (for multi-server mode)
 
         Returns:
             Login response with JWT tokens and user data
@@ -256,7 +261,8 @@ class BackendAPIClient:
                     "email": email,
                     "password": password,
                     "telegram_user_id": telegram_user_id,
-                    "session_token": session_token
+                    "session_token": session_token,
+                    "server_id": server_id
                 },
                 timeout=30.0  # 30 seconds timeout
             )
@@ -298,6 +304,52 @@ class BackendAPIClient:
                 "message": "Eroare de conexiune"
             }
 
+    async def switch_server(
+        self,
+        jwt_token: str,
+        oracle_username: str,
+        new_server_id: str,
+        oracle_password: str = None
+    ) -> dict:
+        """
+        Switch the active Oracle server for the authenticated user.
+
+        Args:
+            jwt_token: Current JWT access token (used for authentication)
+            oracle_username: Oracle username of the current user
+            new_server_id: Target Oracle server ID
+            oracle_password: Oracle password on the new server (required if servers have different passwords)
+
+        Returns:
+            Dict with success, access_token, refresh_token, message
+        """
+        try:
+            if not self.client or self.client.is_closed:
+                self.client = AsyncClient(base_url=self.base_url, timeout=REQUEST_TIMEOUT)
+
+            payload = {"oracle_username": oracle_username, "new_server_id": new_server_id}
+            if oracle_password:
+                payload["oracle_password"] = oracle_password
+
+            response = await self.client.post(
+                "/api/telegram/auth/switch-server",
+                json=payload,
+                headers=self._get_auth_headers(jwt_token)
+            )
+            response.raise_for_status()
+            return response.json()
+
+        except httpx.HTTPStatusError as e:
+            logger.error(f"Switch server HTTP error: {e.response.status_code}")
+            try:
+                return {"success": False, "message": e.response.json().get("detail", "Eroare")}
+            except Exception:
+                return {"success": False, "message": "Eroare la schimbarea serverului"}
+
+        except Exception as e:
+            logger.error(f"Switch server error: {e}")
+            return {"success": False, "message": "Eroare de conexiune"}
+
     async def get_user_companies(self, jwt_token: str) -> List[Dict[str, Any]]:
         """
         Get list of companies the user has access to.