fix(laravel): apply runtime DB config and startup entrypoint

Laravel images no longer bake config:cache at build time, which ignored
K8s DB env vars. Add DB_CONNECTION, clear config on boot, generate APP_KEY
when missing, run migrations, and rebuild caches at container start.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/kubernetes/kubernetes.service.ts

@@ -435,7 +435,14 @@ export class KubernetesService implements OnModuleInit {
       (ctx.runtime === AppRuntime.LARAVEL || ctx.runtime === AppRuntime.PHP) &&
       ctx.databaseType !== DatabaseType.NONE
     ) {
+      const dbConnection =
+        ctx.databaseType === DatabaseType.POSTGRESQL
+          ? 'pgsql'
+          : ctx.databaseType === DatabaseType.MONGODB
+            ? 'mongodb'
+            : 'mysql';
       extraEnv.push(
+        { name: 'DB_CONNECTION', value: dbConnection },
         { name: 'DB_DATABASE', value: ctx.appName.replace(/-/g, '_') },
         { name: 'DB_USERNAME', valueFrom: { secretKeyRef: { name: `${ctx.appName}-db-secret`, key: 'username' } } },
       );