Return recipe media_type from cache endpoint

When cache metadata has type "recipe", return that instead of
auto-detecting (which returns "unknown" for YAML files). This
ensures L2 can properly register recipes as inputs.

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

server.py

@@ -2003,7 +2003,12 @@ async def get_cached(content_hash: str, request: Request):
 
         ipfs_cid = cache_item.get("ipfs_cid") if cache_item else None
         file_size = cache_path.stat().st_size
-        media_type = detect_media_type(cache_path)
+        # Use stored type from metadata, fall back to auto-detection
+        stored_type = meta.get("type") if meta else None
+        if stored_type == "recipe":
+            media_type = "recipe"
+        else:
+            media_type = detect_media_type(cache_path)
         logger.info(f"get_cached: JSON response, ipfs_cid={ipfs_cid[:16] if ipfs_cid else 'None'}..., took {time.time()-start:.3f}s")
         return {
             "content_hash": content_hash,