feat: Gitea Webhook, IMAP, Settings & Deployment docs

- Webhook route and Gitea integration
- IMAP service and Nextcloud/Porkbun setup docs
- Settings UI improvements and API updates
- SSH/Webhook fix prompt for emailsorter.webklar.com
- Bootstrap, config and AI sorter updates

docs/deployment/WEBHOOK_QUICK_START.md

@@ -27,8 +27,9 @@ USE_PM2=true
 1. Gehe zu deinem Repository → **Settings** → **Webhooks**
 2. Klicke **Add Webhook** → **Gitea**
 3. Fülle aus:
-   - **Target URL:** `https://emailsorter.webklar.com/api/webhook/gitea`
+   - **Target URL:** `https://emailsorter.webklar.com/api/webhook/gitea` (Produktion)
    - **Secret:** `dein_generiertes_secret_hier` (aus Schritt 1)
+   - **Authorization Header (optional):** `Bearer dein_generiertes_secret_hier` (gleicher Wert wie Secret)
    - **Trigger On:** ✅ **Push Events**
    - **Branch Filter:** `main` oder `master`
 4. Klicke **Add Webhook**