Add Q&A answered email template to admin Email Templates panel; v1.0.11

- content.ts: add qaAnsweredEmailSubject/Body/CtaLabel/Signoff fields + defaults
- email.js: buildQuestionAnsweredEmailTemplate reads from cachedSiteContent
- AdminPage.tsx: add EmailTemplateCard entry for Q&A answered notification

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.0.10",
+  "version": "1.0.11",
   "type": "module",
   "scripts": {
     "dev": "vite",