feat: add container config to apps and default config to environments

- V5 migration: container_config JSONB + updated_at on apps,
  default_container_config JSONB on environments
- App/Environment records updated with new fields
- PUT /apps/{id}/container-config endpoint for per-app config
- PUT /admin/environments/{id}/default-container-config for env defaults
- GET /apps now supports optional environmentId (lists all when omitted)
- AppRepository.findAll() for cross-environment app listing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/resources/db/migration/V5__app_container_config.sql

@@ -0,0 +1,5 @@
+-- Add container config to apps and environment defaults
+ALTER TABLE apps ADD COLUMN container_config JSONB NOT NULL DEFAULT '{}';
+ALTER TABLE apps ADD COLUMN updated_at TIMESTAMPTZ NOT NULL DEFAULT now();
+
+ALTER TABLE environments ADD COLUMN default_container_config JSONB NOT NULL DEFAULT '{}';