feat(watchers): add Rust-powered watcher backend with runtime fallback and cross-platform test coverage

ts/watchers/index.ts

@@ -4,18 +4,27 @@ import type { IWatcher, IWatcherOptions, IWatchEvent, TWatchEventType } from './
 export type { IWatcher, IWatcherOptions, IWatchEvent, TWatchEventType };
 
 /**
- * Creates a platform-appropriate file watcher based on the current runtime
- * Uses @push.rocks/smartenv for runtime detection
+ * Creates a file watcher, preferring the Rust backend when available.
+ * Falls back to chokidar (Node.js/Bun) or Deno.watchFs based on runtime.
  */
 export async function createWatcher(options: IWatcherOptions): Promise<IWatcher> {
+  // Try Rust watcher first (works on all runtimes via smartrust IPC)
+  try {
+    const { RustWatcher } = await import('./watcher.rust.js');
+    if (await RustWatcher.isAvailable()) {
+      return new RustWatcher(options);
+    }
+  } catch {
+    // Rust watcher not available, fall back
+  }
+
+  // Fall back to runtime-specific watchers
   const env = new Smartenv();
 
   if (env.isDeno) {
-    // Deno runtime - use Deno.watchFs
     const { DenoWatcher } = await import('./watcher.deno.js');
     return new DenoWatcher(options);
   } else {
-    // Node.js or Bun - both use fs.watch (Bun has Node.js compatibility)
     const { NodeWatcher } = await import('./watcher.node.js');
     return new NodeWatcher(options);
   }