Remove static JSON files and seed step; migrate site settings to Postgres

All content (recipes + imprint/privacy settings) now lives exclusively in
Postgres. The app no longer requires a seed step on first deploy.

Changes:
- helpers.php: load_site_settings() returns defaults when site_settings
  table is empty instead of throwing DatabaseUnavailableException; removes
  legacy JSONB migration path
- data/recipes.json, data/site.json: deleted (content already in DB)
- scripts/db-seed.php: deleted (no longer needed)
- docker-compose.yml: remove RUN_DB_SEED env var and data/ volume mount
- docker/entrypoint.sh: remove RUN_DB_SEED seed block
- docs/COOLIFY.md: update deployment guide to reflect seedless workflow
- .claude/launch.json: add dev server configurations for preview tool

Fresh deploys now start with placeholder legal pages and an empty recipe
list; the admin fills in real content via /admin.php without any CLI step.

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

Dockerfile

@@ -24,9 +24,7 @@ WORKDIR /var/www/html
 COPY --chown=www-data:www-data . /var/www/html
 
 RUN sed -i 's/\r$//' /var/www/html/docker/entrypoint.sh \
-    && chmod +x /var/www/html/docker/entrypoint.sh \
-    && mkdir -p /var/www/html/data \
-    && chown -R www-data:www-data /var/www/html/data
+    && chmod +x /var/www/html/docker/entrypoint.sh
 
 EXPOSE 80