Fix duplicate mirror-watcher messages and shutdown crash

- mirror-watcher: use watcher.once('ready') instead of .on() to prevent
  chokidar from firing the handler multiple times on macOS with
  non-existent watch paths (FSEvents quirk)

- embedder: add disposeModels() that calls pipe.dispose() on each ONNX
  pipeline before process exit

- project-manager: call disposeModels() in shutdown() to explicitly free
  ONNX sessions; prevents 'mutex lock failed: Invalid argument' crash
  on macOS during process teardown

Author: prih

src/lib/embedder.ts

@@ -96,6 +96,15 @@ export function resetEmbedder(): void {
   _pipeCache.clear();
 }
 
+/** Dispose all loaded ONNX pipelines. Call before process.exit() to avoid macOS mutex crash. */
+export async function disposeModels(): Promise<void> {
+  for (const pipe of _pipeCache.values()) {
+    try { await pipe.dispose(); } catch { /* ignore */ }
+  }
+  _models.clear();
+  _pipeCache.clear();
+}
+
 // Vectors are L2-normalized → dot product = cosine similarity
 export function cosineSimilarity(a: number[], b: number[]): number {
   if (a.length !== b.length) return 0;

src/lib/mirror-watcher.ts

@@ -498,7 +498,7 @@ export function startMirrorWatcher(config: MirrorWatcherConfig): WatcherHandle {
   watcher.on('add', handleAddOrChange);
   watcher.on('change', handleAddOrChange);
   watcher.on('unlink', handleUnlink);
-  watcher.on('ready', () => {
+  watcher.once('ready', () => {
     const watched = ['.notes/', '.tasks/'];
     if (config.skillManager) watched.push('.skills/');
     process.stderr.write(`[mirror-watcher] Watching ${watched.join(', ')} in ${config.projectDir}\n`);

src/lib/project-manager.ts

@@ -1,5 +1,5 @@
 import { EventEmitter } from 'events';
-import { loadModel, embed, embedQuery } from '@/lib/embedder';
+import { loadModel, embed, embedQuery, disposeModels } from '@/lib/embedder';
 import { loadGraph, saveGraph, type DocGraph, DocGraphManager } from '@/graphs/docs';
 import { loadCodeGraph, saveCodeGraph, type CodeGraph, CodeGraphManager } from '@/graphs/code';
 import { loadKnowledgeGraph, saveKnowledgeGraph, KnowledgeGraphManager } from '@/graphs/knowledge';
@@ -463,6 +463,7 @@ export class ProjectManager extends EventEmitter {
     }
     this.projects.clear();
     this.workspaces.clear();
+    await disposeModels();
     process.stderr.write('[project-manager] Shutdown complete\n');
   }