fix(design): dump hygiene covers CSS URLs, srcdoc, and handlers; dumps persist owner-only; ignore prose treats repo config as evidence

- The dump script cuts query strings from CSS url() in style attributes,
  <style> nodes, and the inlined stylesheets (signed asset URLs), empties
  srcdoc, and covers background and xlink:href.
- Persisted dumps are chmod 600; MEDIUM redaction findings persist (an
  authenticated page shows emails) and the prose says so; earlier runs'
  dumps are swept before the first dump of a run unless --keep-dom.
- The Aside dump prose asks for `'` in a pasted URL to be percent-encoded
  (a bare single quote would end the script) and never to paste an unread
  URL.
- Repo-config ignores are evidence, not settled decisions, in /review,
  /ship, and design-review's probe prose; the scan JSON's text fields are
  named as untrusted.
- design-html's skeleton ceiling is re-measured (54,545); ship goldens
  refreshed for the checklist prose.

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

test/impeccable-fixtures.test.ts

@@ -151,7 +151,7 @@ describe('DOM_DUMP_SCRIPT contract', () => {
     expect(DOM_DUMP_SCRIPT).toContain(DOM_DUMP_NOTE_PREFIX);
     for (const rule of ['querySelectorAll("script")', 'querySelectorAll("textarea")', 'value.length > 32',
       'name === "content" && el.nodeName === "META"', 'cutQuery(value)', 'value.length > 1024',
-      'gstack-stripped', 'cloneLinks[i].remove()', 'querySelectorAll("style")', 'querySelectorAll("template, noscript")', 'name.indexOf("on") === 0']) {
+      'gstack-stripped', 'cloneLinks[i].remove()', 'querySelectorAll("style")', 'querySelectorAll("template, noscript")', 'name.indexOf("on") === 0', 'name === "srcdoc"', 'cleanCss(value)', '"xlink:href"']) {
       expect(DOM_DUMP_SCRIPT).toContain(rule);
     }
   });