chore: httpx retry transport + healthcheck stdlib + mypy config

- mcp_common/http.py: nuovo helper async_client() con
  AsyncHTTPTransport(retries=3) per gestire connection error transient
  + call_with_retry() generic async retry decorator. Sostituite 25
  occorrenze httpx.AsyncClient(...) in deribit/hyperliquid/sentiment/
  macro client. 5 nuovi test.

- Dockerfile healthcheck: passato da python+httpx subprocess a
  stdlib urllib.request.urlopen() su tutti i 6 servizi MCP. Zero
  dipendenze esterne nel runtime check, timeout esplicito 3s, image
  leggermente più snella.

- pyproject.toml: aggiunto [tool.mypy] python_version=3.13 con
  mypy_path multi-package + override ignore_missing_imports per i
  vendor SDK (pybit, alpaca, hyperliquid, pythonjsonlogger). mypy 1.20
  in dev deps; ruff pinned 0.5.x. mcp_common passa mypy clean; 44
  errori tipo pre-esistenti nei servizi affiorati ma non bloccanti —
  fix da pianificare separatamente.

- 455 test verdi.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

services/mcp-hyperliquid/src/mcp_hyperliquid/client.py

@@ -8,6 +8,7 @@ from typing import Any
 
 import httpx
 from mcp_common import indicators as ind
+from mcp_common.http import async_client
 
 BASE_LIVE = "https://api.hyperliquid.xyz"
 BASE_TESTNET = "https://api.hyperliquid-testnet.xyz"
@@ -86,7 +87,7 @@ class HyperliquidClient:
 
     async def _post(self, payload: dict[str, Any]) -> Any:
         """POST JSON to the /info endpoint."""
-        async with httpx.AsyncClient(timeout=15) as http:
+        async with async_client(timeout=15.0) as http:
             resp = await http.post(f"{self.base_url}/info", json=payload)
             resp.raise_for_status()
             return resp.json()
@@ -295,7 +296,7 @@ class HyperliquidClient:
         spot_price: float | None = None
         spot_source = "coinbase"
         try:
-            async with httpx.AsyncClient(timeout=8) as c:
+            async with async_client(timeout=8.0) as c:
                 resp = await c.get(f"https://api.coinbase.com/v2/prices/{asset}-USD/spot")
             if resp.status_code == 200:
                 spot_price = float(resp.json().get("data", {}).get("amount"))
@@ -303,7 +304,7 @@ class HyperliquidClient:
             spot_price = None
         if spot_price is None:
             try:
-                async with httpx.AsyncClient(timeout=8) as c:
+                async with async_client(timeout=8.0) as c:
                     resp = await c.get(
                         "https://api.kraken.com/0/public/Ticker", params={"pair": f"{asset}USD"}
                     )