fix: execute all-complete reaction and guard workspace postCreate

- summary.all_complete reactions now execute in pollAll() after emission
- workspace.postCreate errors trigger workspace cleanup to prevent leaks

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/core/src/lifecycle-manager.ts

@@ -446,6 +446,15 @@ export function createLifecycleManager(deps: LifecycleManagerDeps): LifecycleMan
         });
         eventBus.emit(event);
         emitToHandlers(event);
+
+        // Execute all-complete reaction if configured
+        const reactionKey = eventToReactionKey("summary.all_complete");
+        if (reactionKey) {
+          const reactionConfig = config.reactions[reactionKey];
+          if (reactionConfig && reactionConfig.auto !== false && reactionConfig.action) {
+            await executeReaction(event, reactionKey, reactionConfig as ReactionConfig);
+          }
+        }
       }
     } catch {
       // Poll cycle failed — will retry next interval

packages/core/src/session-manager.ts

@@ -184,9 +184,18 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
       });
       workspacePath = wsInfo.path;
 
-      // Run post-create hooks
+      // Run post-create hooks — clean up workspace on failure
       if (plugins.workspace.postCreate) {
-        await plugins.workspace.postCreate(wsInfo, project);
+        try {
+          await plugins.workspace.postCreate(wsInfo, project);
+        } catch (err) {
+          try {
+            await plugins.workspace.destroy(workspacePath);
+          } catch {
+            /* best effort */
+          }
+          throw err;
+        }
       }
     }