Create ensembl.py

mcp/ensembl.py

@@ -0,0 +1,11 @@
+### `ensembl.py` – species-agnostic xref  
+```python
+import httpx, asyncio
+from functools import lru_cache
+_URL="https://rest.ensembl.org/xrefs/symbol/homo_sapiens/{}?content-type=application/json"
+@lru_cache(maxsize=512)
+async def fetch_ensembl(sym:str):
+    async with httpx.AsyncClient(timeout=8) as c:
+        r=await c.get(_URL.format(sym)); 
+        return r.json()[0] if r.status_code==200 and r.json() else {}
+``` :contentReference[oaicite:8]{index=8}