chore: harden local dev environment

next.config.ts

@@ -2,6 +2,32 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   outputFileTracingRoot: process.cwd(),
+  webpack(config, { dev }) {
+    if (dev) {
+      config.watchOptions = {
+        ...config.watchOptions,
+        ignored: [
+          "**/.agents/**",
+          "**/.claude/**",
+          "**/.codex/**",
+          "**/.cursor/**",
+          "**/.data/**",
+          "**/.git/**",
+          "**/.next/**",
+          "**/.pi/**",
+          "**/.playwright-mcp/**",
+          "**/.serena/**",
+          "**/.spec-workflow/**",
+          "**/.trae/**",
+          "**/.trellis/**",
+          "**/output/**",
+          "**/tmp/**",
+        ],
+      };
+    }
+
+    return config;
+  },
 };
 
 export default nextConfig;