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>

docker/entrypoint.sh

@@ -19,10 +19,5 @@ done
 echo "[flixcooks] Applying schema..."
 php -r "require 'helpers.php'; require_database(); echo \"schema ok\n\";"
 
-if [ "${RUN_DB_SEED:-false}" = "true" ]; then
-  echo "[flixcooks] Seeding recipes from data/recipes.json..."
-  php scripts/db-seed.php
-fi
-
 echo "[flixcooks] Starting Apache..."
 exec "$@"