Add Docker build with Gitea Actions CI

- Add Dockerfile with Python 3.13 + uv
- Add Gitea Actions workflow for auto-build on push
- Add deposit_api.py for balance management
- Update api_server.py with domain registration endpoint

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

deposit_api.py

@@ -0,0 +1,40 @@
+"""
+Deposit API Client - telegram-bot-workers deposit API 연동
+"""
+
+import os
+import httpx
+from dotenv import load_dotenv
+
+load_dotenv()
+
+DEPOSIT_API_URL = os.getenv("DEPOSIT_API_URL", "https://telegram-summary-bot.kappa-d8e.workers.dev")
+DEPOSIT_API_SECRET = os.getenv("DEPOSIT_API_SECRET", "")
+
+
+async def get_balance(telegram_id: str) -> dict:
+    """사용자 예치금 잔액 조회"""
+    async with httpx.AsyncClient() as client:
+        response = await client.get(
+            f"{DEPOSIT_API_URL}/api/deposit/balance",
+            params={"telegram_id": telegram_id},
+            headers={"X-API-Key": DEPOSIT_API_SECRET},
+            timeout=10.0,
+        )
+        return response.json()
+
+
+async def deduct_balance(telegram_id: str, amount: int, reason: str) -> dict:
+    """사용자 예치금 차감"""
+    async with httpx.AsyncClient() as client:
+        response = await client.post(
+            f"{DEPOSIT_API_URL}/api/deposit/deduct",
+            json={
+                "telegram_id": telegram_id,
+                "amount": amount,
+                "reason": reason,
+            },
+            headers={"X-API-Key": DEPOSIT_API_SECRET},
+            timeout=10.0,
+        )
+        return response.json()