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>

scripts/db-seed.php

@@ -1,43 +0,0 @@
-<?php
-/**
- * Einmaliger Import aus data/recipes.json in die relationale DB.
- * Die Website liest zur Laufzeit nur noch aus Postgres.
- *
- *   php scripts/db-seed.php
- */
-require_once dirname(__DIR__) . '/helpers.php';
-
-$seedPath = dirname(__DIR__) . '/data/recipes.json';
-if (!file_exists($seedPath)) {
-    fwrite(STDERR, "Seed-Datei fehlt: data/recipes.json\n");
-    exit(1);
-}
-
-$raw = file_get_contents($seedPath);
-$recipes = json_decode($raw, true);
-if (!is_array($recipes)) {
-    fwrite(STDERR, "Ungültiges JSON in data/recipes.json\n");
-    exit(1);
-}
-
-try {
-    $pdo = require_database();
-} catch (DatabaseUnavailableException $e) {
-    fwrite(STDERR, $e->getMessage() . "\n");
-    exit(1);
-}
-
-$count = 0;
-foreach ($recipes as $recipe) {
-    if (!is_array($recipe) || empty($recipe['slug'])) {
-        continue;
-    }
-    if (save_recipe($recipe, $pdo)) {
-        $count++;
-        echo "  + {$recipe['slug']}\n";
-    } else {
-        fwrite(STDERR, "  ! Fehler bei {$recipe['slug']}\n");
-    }
-}
-
-echo "\nImport abgeschlossen: {$count} Rezepte.\n";