Initial project setup with env template and gitignore

- .gitignore: Java/Maven, Node.js, IDE, OS, credentials
- .env.sample: backend + frontend environment variable template
- README.md: project overview and getting started guide
- CLAUDE.md: development rules and guidelines
- docs/: SUNDOL spec and design patterns guide

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

README.md

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+# SUNDOL
+
+**Smart Unified Natural Dog-Operated Layer**
+
+Personal Knowledge House · AI Assistant · Productivity Hub
+
+## Features
+
+- **Knowledge Ingestion** — YouTube, blog, news, raw text 자동 수집 및 처리
+- **Semantic Search** — Oracle 23ai VECTOR 기반 의미 검색
+- **AI Chat (RAG)** — 지식 기반 대화, 출처 인용
+- **Study Cards (SRS)** — SM-2 간격 반복 학습 카드
+- **Todos** — 작업/하위작업 관리
+- **Habit Tracker** — 습관 추적, 스트릭 관리
+
+## Tech Stack
+
+| Layer | Technology |
+|-------|-----------|
+| Backend | Spring Boot 3, Java 21 |
+| Frontend | Next.js 14, TypeScript, Tailwind CSS |
+| Database | Oracle 23ai (VECTOR support) |
+| AI | OCI Generative AI (Cohere / Llama) |
+| Auth | Google SSO + JWT |
+| Cache | Redis |
+
+## Getting Started
+
+```bash
+# 1. 환경변수 설정
+cp .env.sample .env
+# .env 파일에 실제 값 입력
+
+# 2. Docker Compose로 실행
+docker-compose up -d
+
+# 3. 개별 실행 (Backend)
+cd sundol-backend
+mvn spring-boot:run
+
+# 4. 개별 실행 (Frontend)
+cd sundol-frontend
+npm install && npm run dev
+```
+
+## Project Structure
+
+```
+sundol/
+├── sundol-backend/      # Spring Boot 3
+├── sundol-frontend/     # Next.js 14
+├── db/migration/        # Flyway SQL scripts
+├── docs/                # Specifications
+├── docker-compose.yml
+├── .env.sample          # Environment variable template
+└── README.md
+```
+
+자세한 스펙은 [docs/SUNDOL_SPEC.md](docs/SUNDOL_SPEC.md) 참조.