v1.2.0: Broadcast emails, webhook admin UI, dynamic sitemap, scripture index

- Admin > Audience > Broadcast Email: compose and send one-off HTML emails
  to all subscribers via Resend batch API; {{name}} personalization; confirm step
- Admin > Configure > Webhooks: CRUD UI for managing POST event webhooks;
  backend GET/POST/DELETE /api/admin-webhooks routes wired to existing state.webhooks
- Sitemap: dynamically appends released study lesson URLs (/study/:slug/:id)
  and episode highlight URLs (/episodes/:id) to /sitemap.xml
- Scripture Index: public /scripture page listing every released lesson grouped
  by study with passage reference links; served by /api/public/scripture-index

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.1.52",
+  "version": "1.2.0",
   "type": "module",
   "scripts": {
     "dev": "vite",