Add ipfs_cid support to asset update endpoint

Allow updating asset's IPFS CID via PATCH endpoint.
Pins content on IPFS when CID is provided.

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

server.py

@@ -143,6 +143,7 @@ class UpdateAssetRequest(BaseModel):
     tags: Optional[list[str]] = None
     metadata: Optional[dict] = None
     origin: Optional[dict] = None
+    ipfs_cid: Optional[str] = None  # IPFS content identifier
 
 
 # ============ Storage (Database) ============
@@ -1596,6 +1597,15 @@ async def update_asset(name: str, req: UpdateAssetRequest, user: User = Depends(
         updates["metadata"] = {**asset.get("metadata", {}), **req.metadata}
     if req.origin is not None:
         updates["origin"] = req.origin
+    if req.ipfs_cid is not None:
+        updates["ipfs_cid"] = req.ipfs_cid
+        # Pin on IPFS
+        try:
+            import ipfs_client
+            if ipfs_client.is_available():
+                ipfs_client.pin(req.ipfs_cid)
+        except Exception as e:
+            logger.warning(f"Failed to pin IPFS content {req.ipfs_cid}: {e}")
 
     # Update asset in database
     updated_asset = await db.update_asset(name, updates)