fix(server): bundle superjson into a single ESM file for the browser

Root cause of ALL client-side JS failing:

superjson internally imports \`copy-anything\` which imports \`is-what\` —
both as bare specifiers. The browser's import map only had an entry for
\`superjson\` itself, so the transitive imports failed with:

  Uncaught TypeError: Failed to resolve module specifier "copy-anything"

Since webjs/core statically re-exports richFetch which statically
imports superjson, the ENTIRE core module failed to load. No components
registered, no events fired, no interactivity.

Fix: instead of serving superjson's raw dist/ files (which contain bare
imports to its deps), the server now bundles superjson + all transitive
deps into a single self-contained ESM file via esbuild on first request.
Result is cached in-process. 11KB minified, zero bare-specifier leaks.

Import map simplified:
  'superjson' → '/__webjs/vendor/superjson.js' (single bundled file)

Removed the old /__webjs/vendor/superjson/* wildcard handler (no longer
needed — one file serves everything).

Also: fixed counter.ts that was broken by a bad sed in the previous
debug commit (stray closing brace).

Verified in production mode (webjs start):
  - /__webjs/vendor/superjson.js → 200 (11KB)
  - All pages 200
  - Counter module 200
  - No console errors
  - 70/70 framework tests pass

Author: vivek7405

examples/blog/components/counter.ts

@@ -8,10 +8,6 @@ export class Counter extends WebComponent {
   static tag = 'my-counter';
   static properties = { count: { type: Number } };
   count = 0;
-  connectedCallback() {
-    super.connectedCallback();
-    console.log('[webjs] counter connected — JS is alive');
-  }
   static styles = css`
     :host {
       display: inline-flex;

packages/server/src/dev.js

@@ -299,15 +299,11 @@ async function handleCore(req, ctx) {
     return fileResponse(abs, { dev, immutable: !dev });
   }
 
-  // Vendored packages (only superjson in v1) — served from node_modules so
-  // browsers can resolve bare specifiers in the import map.
-  if (path.startsWith('/__webjs/vendor/superjson/')) {
-    const rel = path.slice('/__webjs/vendor/superjson/'.length);
-    const root = locatePackageDir(appDir, 'superjson');
-    if (!root) return new Response('superjson not installed', { status: 404 });
-    const abs = resolve(root, rel);
-    if (!abs.startsWith(root)) return new Response('forbidden', { status: 403 });
-    return fileResponse(abs, { dev, immutable: !dev });
+  // Vendored superjson — served as a single pre-bundled ESM file so its
+  // transitive deps (copy-anything, is-what) don't need their own
+  // import-map entries. Bundled lazily on first request via esbuild.
+  if (path === '/__webjs/vendor/superjson.js') {
+    return serveBundledSuperjson(appDir, dev);
   }
 
   // Prod bundle (if present)
@@ -687,6 +683,45 @@ async function exists(p) {
  * @param {string} abs
  * @param {boolean} dev
  */
+/** @type {string | null} */
+let _superjsonBundle = null;
+
+/**
+ * Serve superjson as a single self-contained ESM file. All transitive deps
+ * (copy-anything, is-what) are inlined by esbuild so the browser only ever
+ * fetches one file and no bare-specifier imports leak.
+ */
+async function serveBundledSuperjson(appDir, dev) {
+  if (!_superjsonBundle) {
+    let build;
+    try { ({ build } = await import('esbuild')); }
+    catch {
+      return new Response('/* esbuild missing */', {
+        status: 500,
+        headers: { 'content-type': 'application/javascript; charset=utf-8' },
+      });
+    }
+    const entryPoint = locatePackageDir(appDir, 'superjson');
+    if (!entryPoint) return new Response('superjson not found', { status: 404 });
+    const result = await build({
+      entryPoints: [join(entryPoint, 'dist', 'index.js')],
+      bundle: true,
+      format: 'esm',
+      target: 'es2022',
+      platform: 'browser',
+      write: false,
+      minify: !dev,
+    });
+    _superjsonBundle = result.outputFiles[0].text;
+  }
+  return new Response(_superjsonBundle, {
+    headers: {
+      'content-type': 'application/javascript; charset=utf-8',
+      'cache-control': dev ? 'no-cache' : 'public, max-age=31536000, immutable',
+    },
+  });
+}
+
 async function tsResponse(abs, dev) {
   let esbuild;
   try { ({ transform: esbuild } = await import('esbuild')); }

packages/server/src/importmap.js

@@ -1,15 +1,16 @@
 /**
  * Build the import map JSON injected into every SSR HTML document.
- * Lets users write bare specifiers (`import { html } from 'webjs'`,
- * `import { parse } from 'superjson'`) without relative paths or a bundler.
+ *
+ * superjson is mapped to a single pre-bundled ESM file (its transitive deps
+ * copy-anything + is-what are inlined by esbuild on first request) so only
+ * ONE fetch is needed and no extra bare-specifier entries leak into the map.
  */
 export function buildImportMap() {
   return {
     imports: {
       'webjs':     '/__webjs/core/index.js',
       'webjs/':    '/__webjs/core/src/',
-      'superjson': '/__webjs/vendor/superjson/dist/index.js',
-      'superjson/': '/__webjs/vendor/superjson/dist/',
+      'superjson': '/__webjs/vendor/superjson.js',
     },
   };
 }