T-1: initialize monorepo structure with backend and frontend scaffolds

Backend: Spring Boot 3.5.11 on Java 25, Maven with wrapper, hexagonal
architecture package layout (domain/application/adapter/config), health
endpoint with integration test. Originally planned for Spring Boot 4.0
but pivoted due to massive package reorganization in 4.0 (see addenda
in research and plan docs).

Frontend: Vue 3 scaffolded via create-vue with TypeScript, Vue Router,
Vitest, ESLint, Prettier. Pivoted from Svelte due to ecosystem maturity
concerns (broken router ecosystem for Svelte 5).

Also: extended .gitignore for Java/Maven and Node/Vue artifacts, updated
CLAUDE.md with tech stack, build commands, agent documentation sections,
and document integrity rule.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/package.json

@@ -0,0 +1,49 @@
+{
+  "name": "frontend",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "run-p type-check \"build-only {@}\" --",
+    "preview": "vite preview",
+    "test:unit": "vitest",
+    "build-only": "vite build",
+    "type-check": "vue-tsc --build",
+    "lint": "run-s lint:*",
+    "lint:oxlint": "oxlint . --fix",
+    "lint:eslint": "eslint . --fix --cache",
+    "format": "prettier --write --experimental-cli src/"
+  },
+  "dependencies": {
+    "vue": "^3.5.29",
+    "vue-router": "^5.0.3"
+  },
+  "devDependencies": {
+    "@tsconfig/node24": "^24.0.4",
+    "@types/jsdom": "^28.0.0",
+    "@types/node": "^24.11.0",
+    "@vitejs/plugin-vue": "^6.0.4",
+    "@vitest/eslint-plugin": "^1.6.9",
+    "@vue/eslint-config-typescript": "^14.7.0",
+    "@vue/test-utils": "^2.4.6",
+    "@vue/tsconfig": "^0.8.1",
+    "eslint": "^10.0.2",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-plugin-oxlint": "~1.50.0",
+    "eslint-plugin-vue": "~10.8.0",
+    "jiti": "^2.6.1",
+    "jsdom": "^28.1.0",
+    "npm-run-all2": "^8.0.4",
+    "oxlint": "~1.50.0",
+    "prettier": "3.8.1",
+    "typescript": "~5.9.3",
+    "vite": "^7.3.1",
+    "vite-plugin-vue-devtools": "^8.0.6",
+    "vitest": "^4.0.18",
+    "vue-tsc": "^3.2.5"
+  },
+  "engines": {
+    "node": "^20.19.0 || >=22.12.0"
+  }
+}