Update effect upload to show IPFS CID

- Display CID instead of content hash after upload
- Update example recipe syntax to use :cid

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

artdag.py

@@ -1017,10 +1017,10 @@ def upload_recipe(filepath):
 @cli.command("upload-effect")
 @click.argument("filepath", type=click.Path(exists=True))
 def upload_effect(filepath):
-    """Upload an effect file. Requires login.
+    """Upload an effect file to IPFS. Requires login.
 
     Effects are Python files with PEP 723 dependencies and @-tag metadata.
-    Returns the content hash for use in recipes.
+    Returns the IPFS CID for use in recipes.
     """
     token_data = load_token()
     if not token_data.get("access_token"):
@@ -1048,7 +1048,7 @@ def upload_effect(filepath):
             result = resp.json()
 
         click.echo(f"Uploaded effect: {result['name']} v{result.get('version', '1.0.0')}")
-        click.echo(f"Content hash: {result['content_hash']}")
+        click.echo(f"CID: {result['cid']}")
         click.echo(f"Temporal: {result.get('temporal', False)}")
         if result.get('params'):
             click.echo(f"Parameters: {', '.join(p['name'] for p in result['params'])}")
@@ -1056,7 +1056,7 @@ def upload_effect(filepath):
             click.echo(f"Dependencies: {', '.join(result['dependencies'])}")
         click.echo()
         click.echo("Use in recipes:")
-        click.echo(f'  (effect {result["name"]} :hash "{result["content_hash"]}")')
+        click.echo(f'  (effect {result["name"]} :cid "{result["cid"]}")')
     except requests.RequestException as e:
         click.echo(f"Upload failed: {e}", err=True)
         sys.exit(1)