Add backend/frontend scaffolding with Oracle ADB wallet config

- Backend: Spring Boot 3 + WebFlux, JWT auth, Oracle ADB wallet,
  8 controllers/services/repositories (Auth~Tag), DTOs, exception handling
- Frontend: Next.js 15, TypeScript, Tailwind CSS, AuthContext,
  7 pages (dashboard, knowledge, chat, study, todos, habits, login)
- DB: V1 migration with 12 tables including VECTOR(1024) + HNSW index
- Ops: PM2 ecosystem config, deploy.sh, start-backend.sh
- CLAUDE.md: DB credentials replaced with env var references

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

sundol-frontend/eslint.config.mjs

@@ -0,0 +1,14 @@
+import { dirname } from "path";
+import { fileURLToPath } from "url";
+import { FlatCompat } from "@eslint/eslintrc";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+const eslintConfig = [...compat.extends("next/core-web-vitals", "next/typescript")];
+
+export default eslintConfig;