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>

datenschutz.php

@@ -2,7 +2,11 @@
 require __DIR__ . '/helpers.php';
 
 $lang     = strtolower((string)(filter_input(INPUT_GET, 'lang', FILTER_SANITIZE_FULL_SPECIAL_CHARS) ?: 'en')) === 'de' ? 'de' : 'en';
-$settings = load_site_settings();
+try {
+    $settings = load_site_settings();
+} catch (DatabaseUnavailableException $e) {
+    handle_database_unavailable($e);
+}
 $privacy  = $settings['privacy'][$lang] ?? ($settings['privacy']['en'] ?? []);
 
 $langSwitchLabel = $lang === 'de' ? 'DE' : 'EN';