feat: add Docker, Drone CI, and k8s deployment manifests

- Dockerfile for Python 3.12 FastAPI app
- Drone CI pipeline to build and push to internal registry
- Kubernetes manifests (Deployment, Service, Secret, Namespace)
- ArgoCD Application for GitOps deployment
- Kustomize base configuration

.dockerignore

@@ -0,0 +1,10 @@
+__pycache__/
+*.pyc
+.env
+.pytest_cache/
+.coverage
+.claude/
+tests/
+*.md
+environment.yml
+test_*.py