Initial commit: Backend API Phase 1a complete

- FastAPI backend with JWT auth
- PostgreSQL database schema
- Trees and Sessions CRUD APIs
- Export functionality (Markdown, Text, HTML)
- Docker setup for local development
- Alembic migrations

backend/app/core/config.py

@@ -0,0 +1,32 @@
+from pydantic_settings import BaseSettings
+from typing import Optional
+
+
+class Settings(BaseSettings):
+    # Application
+    APP_NAME: str = "Troubleshooting Decision Tree"
+    DEBUG: bool = False
+    API_V1_PREFIX: str = "/api/v1"
+
+    # Database
+    DATABASE_URL: str = "postgresql+asyncpg://postgres:postgres@localhost:5432/decision_tree"
+    DATABASE_URL_SYNC: str = "postgresql://postgres:postgres@localhost:5432/decision_tree"
+
+    # JWT Settings
+    SECRET_KEY: str = "your-secret-key-change-in-production-use-openssl-rand-hex-32"
+    ALGORITHM: str = "HS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 15
+    REFRESH_TOKEN_EXPIRE_DAYS: int = 7
+
+    # Security
+    BCRYPT_ROUNDS: int = 12
+
+    # CORS
+    CORS_ORIGINS: list[str] = ["http://localhost:3000", "http://localhost:5173"]
+
+    class Config:
+        env_file = ".env"
+        case_sensitive = True
+
+
+settings = Settings()