fix: allow notify reactions when auto is false, clean up reserved IDs on spawn failure

- Reactions with action: "notify" bypass the auto: false gate so
  merge-ready notifications fire for approved-and-green config
- All spawn failure paths now delete the reserved session metadata file

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

packages/core/src/lifecycle-manager.ts

@@ -418,11 +418,14 @@ export function createLifecycleManager(deps: LifecycleManagerDeps): LifecycleMan
             ? { ...globalReaction, ...projectReaction }
             : globalReaction;
 
-          if (reactionConfig && reactionConfig.auto !== false && reactionConfig.action) {
+          if (reactionConfig && reactionConfig.action) {
+            // auto: false skips automated agent actions but still allows notifications
+            if (reactionConfig.auto !== false || reactionConfig.action === "notify") {
               await executeReaction(event, reactionKey, reactionConfig as ReactionConfig);
             }
           }
         }
+      }
     } else {
       // No transition but track current state
       states.set(session.id, newStatus);
@@ -467,11 +470,13 @@ export function createLifecycleManager(deps: LifecycleManagerDeps): LifecycleMan
         const reactionKey = eventToReactionKey("summary.all_complete");
         if (reactionKey) {
           const reactionConfig = config.reactions[reactionKey];
-          if (reactionConfig && reactionConfig.auto !== false && reactionConfig.action) {
+          if (reactionConfig && reactionConfig.action) {
+            if (reactionConfig.auto !== false || reactionConfig.action === "notify") {
               await executeReaction(event, reactionKey, reactionConfig as ReactionConfig);
             }
           }
         }
+      }
     } catch {
       // Poll cycle failed — will retry next interval
     } finally {

packages/core/src/session-manager.ts

@@ -192,6 +192,7 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
     // Create workspace (if workspace plugin is available)
     let workspacePath = project.path;
     if (plugins.workspace) {
+      try {
         const wsInfo = await plugins.workspace.create({
           projectId: spawnConfig.projectId,
           project,
@@ -200,7 +201,7 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
         });
         workspacePath = wsInfo.path;
 
-      // Run post-create hooks — clean up workspace on failure (skip if project root)
+        // Run post-create hooks — clean up workspace on failure
         if (plugins.workspace.postCreate) {
           try {
             await plugins.workspace.postCreate(wsInfo, project);
@@ -215,6 +216,15 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
             throw err;
           }
         }
+      } catch (err) {
+        // Clean up reserved session ID on workspace failure
+        try {
+          deleteMetadata(config.dataDir, sessionId, false);
+        } catch {
+          /* best effort */
+        }
+        throw err;
+      }
     }
 
     // Get agent launch config and create runtime — clean up workspace on failure
@@ -242,7 +252,7 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
         },
       });
     } catch (err) {
-      // Clean up workspace if agent config or runtime creation failed
+      // Clean up workspace and reserved ID if agent config or runtime creation failed
       if (plugins.workspace && workspacePath !== project.path) {
         try {
           await plugins.workspace.destroy(workspacePath);
@@ -250,6 +260,11 @@ export function createSessionManager(deps: SessionManagerDeps): SessionManager {
           /* best effort */
         }
       }
+      try {
+        deleteMetadata(config.dataDir, sessionId, false);
+      } catch {
+        /* best effort */
+      }
       throw err;
     }