Fix IPFS upload: sync instead of background task

The background IPFS upload task was running on workers that don't have
the file locally, causing uploads to fail silently. Now uploads go to
IPFS synchronously so the IPFS CID is available immediately.

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

streaming/stream_sexp_generic.py

@@ -414,7 +414,6 @@ class StreamInterpreter:
                                 self._load_effect(resolved)
                             else:
                                 raise RuntimeError(f"Could not resolve include name '{fname}' - make sure it's uploaded and you're logged in")
-                                raise RuntimeError(f"Could not resolve include name '{fname}' - make sure it's uploaded and you're logged in")
                             i += 2
                         else:
                             i += 1