Refactor to Vue 3 + FastAPI + SQLite architecture

- Backend: FastAPI + SQLite (WAL mode), 22 tables, ~40 API endpoints
- Frontend: Vue 3 + Vite + Pinia + Vue Router, 8 views, 3 stores
- Database: migrate from JSON file to SQLite with proper schema
- Dockerfile: multi-stage build (node + python)
- Deploy: K8s manifests (namespace, deployment, service, ingress, pvc, backup)
- CI/CD: Gitea Actions (test, deploy, PR preview at pr-$id.planner.oci.euphon.net)
- Tests: 20 Cypress E2E test files, 196 test cases, ~85% coverage
- Doc: test-coverage.md with full feature coverage report

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

frontend/cypress.config.js

@@ -0,0 +1,13 @@
+import { defineConfig } from 'cypress'
+
+export default defineConfig({
+  e2e: {
+    baseUrl: 'http://localhost:5173',
+    supportFile: 'cypress/support/e2e.js',
+    specPattern: 'cypress/e2e/**/*.cy.{js,ts}',
+    viewportWidth: 1280,
+    viewportHeight: 800,
+    video: true,
+    videoCompression: false,
+  },
+})