fix(performance): strip inert HTML to a fixpoint

Repeat the comment and inline-body removal until nothing changes, so the
pieces around a removed comment cannot assemble into a tag that a single
pass would then count (CodeQL: incomplete multi-character sanitization).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/performance/measure-initial-bytes.mjs

@@ -66,7 +66,17 @@ function classify(tag, attributes) {
  * inline script element is still seen.
  */
 export function stripInertHtml(html) {
-    return html.replace(HTML_COMMENT, '').replace(INLINE_ELEMENT_BODY, '$1$3');
+    // Repeat until nothing changes: a single pass can expose a new comment or
+    // element body assembled from the pieces around a removed one.
+    let previous;
+    let stripped = html;
+    do {
+        previous = stripped;
+        stripped = stripped
+            .replace(HTML_COMMENT, '')
+            .replace(INLINE_ELEMENT_BODY, '$1$3');
+    } while (stripped !== previous);
+    return stripped;
 }
 
 /**

tools/performance/measure-initial-bytes.test.mjs

@@ -132,7 +132,13 @@ test('ignores commented-out tags and tag-like text inside inline scripts and sty
         extractInitialResources(html).map((resource) => resource.url),
         ['assets/app-config.js', 'main.js']
     );
-    assert.equal(stripInertHtml('<script>1 < 2</script>'), '<script></script>');
+    assert.equal(stripInertHtml('<script>1 < 2</script>'), '<script></script>'); // Pieces around a removed comment must not assemble into a live tag.
+    assert.deepEqual(
+        extractInitialResources(
+            '<!<!-- a -->-- <script src="x.js"></script> -->'
+        ),
+        []
+    );
 });
 
 test('counts a file once per distinct request URL', async () => {