feat: Add Python SDK with async/await support and comprehensive Telecom Platform API integration

- Add TelecomSDK class with async context manager and aiohttp ClientSession with 30s timeout, 3 retries
- Add subscriber management: get_subscriber, list_subscribers with pagination/status filter, create_subscriber, update_subscriber, suspend_subscriber, activate_subscriber, terminate_subscriber
- Add usage tracking: get_usage_stats with date range, list_usage_events with filtering, get_real_time_usage

sdk/python/telecom_sdk/__init__.py

@@ -0,0 +1,30 @@
+from .client import TelecomSDK
+from .types import (
+    Subscriber,
+    UsageStats,
+    PaymentTransaction,
+    SystemStats,
+    HealthStatus,
+    WebSocketMessage,
+)
+from .exceptions import (
+    TelecomError,
+    AuthenticationError,
+    APIError,
+    NetworkError,
+)
+
+__version__ = "1.0.0"
+__all__ = [
+    "TelecomSDK",
+    "Subscriber",
+    "UsageStats", 
+    "PaymentTransaction",
+    "SystemStats",
+    "HealthStatus",
+    "WebSocketMessage",
+    "TelecomError",
+    "AuthenticationError",
+    "APIError",
+    "NetworkError",
+]