Add IPFS CID support for asset lookup

- Upload endpoint returns both CID and content_hash
- Cache manager handles both SHA3-256 hashes and IPFS CIDs
- get_by_cid() fetches from IPFS if not cached locally
- Execute tasks support :cid in addition to :hash

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

cache_manager.py

@@ -427,8 +427,17 @@ class L1CacheManager:
         """Get cached file path by node_id."""
         return self.cache.get(node_id)
 
+    def _is_ipfs_cid(self, identifier: str) -> bool:
+        """Check if identifier looks like an IPFS CID."""
+        # CIDv0 starts with "Qm", CIDv1 starts with "bafy" or other multibase prefixes
+        return identifier.startswith("Qm") or identifier.startswith("bafy") or identifier.startswith("baf")
+
     def get_by_content_hash(self, content_hash: str) -> Optional[Path]:
-        """Get cached file path by content_hash. Falls back to IPFS if not in local cache."""
+        """Get cached file path by content_hash or IPFS CID. Falls back to IPFS if not in local cache."""
+
+        # If it looks like an IPFS CID, use get_by_cid instead
+        if self._is_ipfs_cid(content_hash):
+            return self.get_by_cid(content_hash)
 
         # Check index first (Redis then local)
         node_id = self._get_content_index(content_hash)
@@ -469,6 +478,32 @@ class L1CacheManager:
 
         return None
 
+    def get_by_cid(self, ipfs_cid: str) -> Optional[Path]:
+        """Get cached file path by IPFS CID. Fetches from IPFS if not in local cache."""
+
+        # Check if we have this CID cached locally (indexed by CID)
+        cached_path = self.legacy_dir / ipfs_cid
+        if cached_path.exists() and cached_path.is_file():
+            return cached_path
+
+        # Check cache directory structure
+        cid_cache_dir = self.cache_dir / ipfs_cid
+        if cid_cache_dir.exists() and cid_cache_dir.is_dir():
+            # Look for output file
+            for f in cid_cache_dir.iterdir():
+                if f.is_file() and not f.name.endswith('.json'):
+                    return f
+
+        # Fetch from IPFS
+        logger.info(f"Fetching from IPFS: {ipfs_cid[:16]}...")
+        recovery_path = self.legacy_dir / ipfs_cid
+        recovery_path.parent.mkdir(parents=True, exist_ok=True)
+        if ipfs_client.get_file(ipfs_cid, recovery_path):
+            logger.info(f"Fetched from IPFS: {recovery_path}")
+            return recovery_path
+
+        return None
+
     def has_content(self, content_hash: str) -> bool:
         """Check if content exists in cache."""
         return self.get_by_content_hash(content_hash) is not None