Fix completed runs not appearing in list + add purge-failed endpoint

- Update save_run_cache to also update actor_id, recipe, inputs on conflict
- Add logging for actor_id when saving runs to run_cache
- Add admin endpoint DELETE /runs/admin/purge-failed to delete all failed runs

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

tasks/__init__.py

@@ -2,9 +2,12 @@
 #
 # Tasks:
 # 1. run_stream - Execute a streaming S-expression recipe
+# 2. upload_to_ipfs - Background IPFS upload for media files
 
 from .streaming import run_stream
+from .ipfs_upload import upload_to_ipfs
 
 __all__ = [
     "run_stream",
+    "upload_to_ipfs",
 ]