feat: implement proto-gen platform

- Config loader with env var expansion and validation
- SQLite database with tasks and toolchain_versions tables
- Gitea REST API client for repository and branch operations
- K8s client for Job lifecycle management (with noop fallback for local dev)
- REST API: tasks CRUD, retry, plugins, version management
- Worker/scheduler with polling, concurrency control, and job tracking
- Static frontend: generate, tasks, settings pages
- Toolchain images: Go and Node.js Dockerfiles with entrypoint scripts
- Helm chart with deployment, service, configmap, ingress, PVC
- Multi-stage Dockerfile for service
- Unit tests for config, database, gitclient, k8s, api, worker
- E2E tests for idempotency, version switch, failure recovery

deploy/helm/proto-gen/templates/pvc.yaml

@@ -0,0 +1,17 @@
+{{- if .Values.persistence.enabled }}
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: {{ .Release.Name }}-data
+  labels:
+    app: {{ .Release.Name }}
+spec:
+  accessModes:
+    - ReadWriteOnce
+  {{- if .Values.persistence.storageClass }}
+  storageClassName: {{ .Values.persistence.storageClass }}
+  {{- end }}
+  resources:
+    requests:
+      storage: {{ .Values.persistence.size }}
+{{- end }}