Remove dead CSS for qa-top-nav and thanks-page Q&A overrides; v1.0.7

These rules became orphaned after converting QuestionsPage to a full site
layout and removing the back-to-site nav link from QASection.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.0.6",
+  "version": "1.0.7",
   "type": "module",
   "scripts": {
     "dev": "vite",