refactor: full-stack restructure with multi-tenancy, workspace management, and K8s diagnostics

- Add Workspace domain (entity, repository, service, handler, DTO)
- Add multi-tenant K8s client with tenant binding and quota management
- Add K8s diagnostics client (instance diagnostics)
- Add authorization middleware (authz package)
- Restructure frontend to feature-based architecture (features/)
- Add User Management page in configuration
- Add AccessDenied page and route guards
- Refactor shared components (form inputs, layout, UI)
- Update Tailwind config for new design system
- Add comprehensive documentation (docs/, tasks/, plans)
- Improve cluster service with better kubeconfig handling
- Add tests for crypto, config, helm client, tenant binding

test/docker-compose.verify.yml

@@ -0,0 +1,61 @@
+# Scope: isolated runtime verification for backend API + PostgreSQL + .env bootstrap without using project fixed container names.
+
+services:
+  postgres:
+    image: postgres:17-alpine
+    container_name: ocdp-verify-postgres
+    restart: "no"
+    environment:
+      POSTGRES_DB: ${POSTGRES_DB:-ocdp}
+      POSTGRES_USER: ${POSTGRES_USER:-postgres}
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-postgres}
+      POSTGRES_INITDB_ARGS: "--encoding=UTF8 --lc-collate=C --lc-ctype=C"
+    ports:
+      - "${VERIFY_POSTGRES_PORT:-15432}:5432"
+    volumes:
+      - ocdp_verify_postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER:-postgres} -d ${POSTGRES_DB:-ocdp}"]
+      interval: 5s
+      timeout: 5s
+      retries: 30
+      start_period: 180s
+    networks:
+      - ocdp-verify-network
+
+  backend:
+    image: golang:1.24-alpine
+    container_name: ocdp-verify-backend
+    restart: "no"
+    working_dir: /src
+    env_file:
+      - path: ../.env
+        required: false
+    environment:
+      ADAPTER_MODE: production
+      PORT: 8080
+      JWT_SECRET: ${JWT_SECRET:-verify-jwt-secret}
+      ENCRYPTION_KEY: ${ENCRYPTION_KEY:-verify-encryption-key}
+      DATABASE_URL: postgresql://${POSTGRES_USER:-postgres}:${POSTGRES_PASSWORD:-postgres}@postgres:5432/${POSTGRES_DB:-ocdp}?sslmode=disable
+    ports:
+      - "${VERIFY_BACKEND_PORT:-18081}:8080"
+    volumes:
+      - ../backend:/src
+    command: >
+      sh -c "
+        apk add --no-cache git &&
+        go run cmd/api/main.go
+      "
+    depends_on:
+      postgres:
+        condition: service_healthy
+    networks:
+      - ocdp-verify-network
+
+networks:
+  ocdp-verify-network:
+    name: ocdp-verify-network
+
+volumes:
+  ocdp_verify_postgres_data:
+    name: ocdp-verify-postgres-data