feat: Add comprehensive API client modules and JWT authentication to Python SDK

- Add pyjwt>=2.10.0 dependency to requirements.txt
- Add AuthProvider class with API key and JWT token support (create_token, validate_token, refresh_token, get_headers methods)
- Add APIClient base class with retry logic, error handling, and async session management
- Add SubscriberAPI module (get, list, create, update, suspend, activate, terminate methods)
- Add UsageAPI module (get_stats, list_events, get_realtime methods

sdk/python/telecom_sdk/websocket.py

@@ -0,0 +1,100 @@
+import json
+import logging
+from typing import Optional, Callable
+import websockets
+from websockets.exceptions import ConnectionClosed
+
+from .types import WebSocketMessage
+from .exceptions import NetworkError
+
+
+class WebSocketClient:
+    """WebSocket client for real-time updates from the Telecom Platform."""
+    
+    def __init__(
+        self,
+        api_url: str,
+        auth_provider,
+        enable_logging: bool = False,
+    ):
+        """
+        Initialize the WebSocket client.
+        
+        Args:
+            api_url: Base URL for the API server
+            auth_provider: Authentication provider instance
+            enable_logging: Enable debug logging
+        """
+        self.api_url = api_url.rstrip('/')
+        self.auth_provider = auth_provider
+        self.enable_logging = enable_logging
+        
+        if enable_logging:
+            self.logger = logging.getLogger(__name__)
+        else:
+            self.logger = logging.getLogger(__name__)
+            self.logger.disabled = True
+        
+        self._websocket: Optional[websockets.WebSocketServerProtocol] = None
+        self._connected = False
+    
+    async def connect(self, message_handler: Callable[[WebSocketMessage], None]) -> None:
+        """
+        Connect to WebSocket for real-time updates.
+        
+        Args:
+            message_handler: Async function to handle WebSocket messages
+        """
+        ws_url = self.api_url.replace("http://", "ws://") + "/ws"
+        headers = self.auth_provider.get_headers()
+        
+        try:
+            self._websocket = await websockets.connect(ws_url, extra_headers=headers)
+            self._connected = True
+            self.logger.info("WebSocket connected")
+            
+            async for message in self._websocket:
+                try:
+                    data = json.loads(message)
+                    ws_message = WebSocketMessage(**data)
+                    await message_handler(ws_message)
+                except json.JSONDecodeError as e:
+                    self.logger.error(f"Failed to decode WebSocket message: {e}")
+                except Exception as e:
+                    self.logger.error(f"Error handling WebSocket message: {e}")
+                    
+        except ConnectionClosed:
+            self.logger.warning("WebSocket connection closed")
+            self._connected = False
+        except Exception as e:
+            self.logger.error(f"WebSocket error: {e}")
+            self._connected = False
+            raise NetworkError(f"WebSocket connection failed: {e}")
+    
+    async def disconnect(self) -> None:
+        """Disconnect from WebSocket."""
+        if self._websocket:
+            await self._websocket.close()
+            self._websocket = None
+            self._connected = False
+            self.logger.info("WebSocket disconnected")
+    
+    def is_connected(self) -> bool:
+        """Check if WebSocket is connected."""
+        return self._connected
+    
+    async def send(self, data: dict) -> None:
+        """
+        Send data through the WebSocket connection.
+        
+        Args:
+            data: Dictionary data to send
+        """
+        if not self._connected or not self._websocket:
+            raise NetworkError("WebSocket is not connected")
+        
+        try:
+            await self._websocket.send(json.dumps(data))
+        except Exception as e:
+            self.logger.error(f"Failed to send WebSocket message: {e}")
+            raise NetworkError(f"Failed to send message: {e}")