Monorepo Integration: Unified Backend, Frontend & Documentation

- Reorganize project into monorepo structure
  - backend/app/ - New FastAPI backend (modular with src/)
  - backend/legacy/ - Legacy database modules (relational & vector)
  - frontend/ - React text editor application

- Add launcher.py for easy full-stack startup
- Complete documentation in README.md
  - Quick start guide
  - API endpoints reference
  - Development setup
  - Troubleshooting

- Refactor main.py to 35 lines (app configuration only)
- Update .gitignore for full-stack project
- Add CHANGELOG.md with version history (v0.1.0-v0.1.1)

Structure is now clean and ready for team collaboration.

backend/app/src/models.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Column, Integer, String
+from sqlalchemy.orm import declarative_base
+
+Base = declarative_base()
+
+
+class SecurityConfig(Base):
+    """Storage for password and recovery key hashes."""
+    __tablename__ = "security_config"
+
+    id = Column(Integer, primary_key=True, index=True)
+    password_hash = Column(String, nullable=False)
+    recovery_key_hash = Column(String, nullable=False)