Auto-Update über Gitea einrichten + Web-Editor + Sync-Verbesserungen

- Thunderbird Auto-Update: update_url im Manifest, updates.json, release.sh
- .xpi neu gebaut (mit update_url, ohne defaults.local.json/Token)
- README + CLAUDE.md: Auto-Update-Doku, Repo muss public bleiben
- web-editor/ (Node/Docker WYSIWYG-Editor) hinzugefügt
- gitea-sync.js + templates_options: bestehende Anpassungen

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-editor/docker-compose.yml

@@ -0,0 +1,20 @@
+services:
+  web-editor:
+    build: .
+    image: hps-vorlagen-web-editor
+    container_name: hps-web-editor
+    restart: unless-stopped
+    ports:
+      - "${HOST_PORT:-8080}:3000"
+    environment:
+      GITEA_URL: ${GITEA_URL}
+      GITEA_OWNER: ${GITEA_OWNER}
+      GITEA_REPO: ${GITEA_REPO}
+      GITEA_BRANCH: ${GITEA_BRANCH:-main}
+      GITEA_TOKEN: ${GITEA_TOKEN}
+      COMMIT_AUTHOR_NAME: ${COMMIT_AUTHOR_NAME:-Web-Editor}
+      COMMIT_AUTHOR_EMAIL: ${COMMIT_AUTHOR_EMAIL:-}
+      BASIC_AUTH_USER: ${BASIC_AUTH_USER:-}
+      BASIC_AUTH_PASS: ${BASIC_AUTH_PASS:-}
+    env_file:
+      - .env