fix(site-builder): make formatHtml quote- and raw-text-aware

Code review found two Important bugs from only <pre> being exempted from
the naive </> tag-boundary scan: a > inside a quoted attribute value split
tags and broke idempotency, and <script>/<style> (declared BLOCK_TAGS but
never given raw-text treatment) let JS/CSS < and > desync sibling nesting.
Adds a quote-aware tag-end scanner, generalizes verbatim handling to
<script>/<style>, and makes close-tag stack popping verify the tag name
before popping instead of blindly popping by position.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

craft/src/utils/format-html.test.ts

@@ -39,3 +39,45 @@ describe('formatHtml', () => {
     expect(formatHtml('</div><p>x</p>')).toBe('</div>\n<p>x</p>');
   });
 });
+
+// Regression coverage from code review: only <pre> was originally exempted
+// from the naive '<'/'>' tag-boundary scan, which let a '>' inside a quoted
+// attribute value corrupt output, and let '<'/'>' inside <script>/<style>
+// content be misparsed as tag boundaries.
+describe('formatHtml - raw content and quoted attributes', () => {
+  test('a ">" inside a quoted attribute value does not split the tag', () => {
+    const src = '<div title="a>b"><p>hi</p></div><footer>bye</footer>';
+    expect(formatHtml(src)).toBe(
+      '<div title="a>b">\n  <p>hi</p>\n</div>\n<footer>bye</footer>',
+    );
+  });
+
+  test('"<" and ">" inside <script> content do not desync sibling nesting', () => {
+    const src = '<div><script>a < b;</script></div><div><script>c < d;</script></div>';
+    expect(formatHtml(src)).toBe(
+      '<div>\n  <script>a < b;</script>\n</div>\n<div>\n  <script>c < d;</script>\n</div>',
+    );
+  });
+
+  test('a CSS child combinator inside <style> content is not treated as markup', () => {
+    const src = '<div><style>div > p { color: red; }</style></div>';
+    expect(formatHtml(src)).toBe(
+      '<div>\n  <style>div > p { color: red; }</style>\n</div>',
+    );
+  });
+
+  test('is idempotent across a quoted ">" attribute and <script> content', () => {
+    const quotedAttr = formatHtml('<div title="a>b"><p>hi</p></div><footer>bye</footer>');
+    expect(formatHtml(quotedAttr)).toBe(quotedAttr);
+
+    const scriptSrc = '<div><script>a < b;</script></div><div><script>c < d;</script></div>';
+    const scripted = formatHtml(scriptSrc);
+    expect(formatHtml(scripted)).toBe(scripted);
+  });
+
+  test('an unclosed <pre> is swallowed verbatim to the end of the document', () => {
+    expect(formatHtml('<div><pre>no closing tag here')).toBe(
+      '<div>\n  <pre>no closing tag here',
+    );
+  });
+});