local dev: .env for local development (gitignored)

- .env.example: template with all service URIs for local development
- LOCAL_DEV.md: guide for running poimen locally
- Production: config.yaml (SOPS-encrypted K8s ConfigMap)
- Local: .env file (gitignored, never committed)
- Application reads from ENV in both cases (K8s ConfigMap + local dotenv)
- Simplifies prod/dev: same code, different config sources

k8s/app/kustomization.yaml

@@ -6,7 +6,6 @@ resources:
   - deployment.yaml
   - service.yaml
   - config.yaml        # Production config (SOPS-encrypted)
-  # config.local.yaml  # Optional: plaintext local/dev overrides
 
 generators:
   - secret-generator.yaml