feat: initial HarborForge project structure

- Docker Compose with MySQL + FastAPI backend
- Issue model with RESOLUTION type (for agent deadlock resolution)
- Project, User, Comment models
- Basic CRUD API endpoints
- .env.example for configuration

backend/app/core/config.py

@@ -0,0 +1,31 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pydantic_settings import BaseSettings
+from typing import Optional
+
+
+class Settings(BaseSettings):
+    DATABASE_URL: str = "mysql+pymysql://harborforge:harborforge_pass@mysql:3306/harborforge"
+    SECRET_KEY: str = "change-me-in-production"
+    LOG_LEVEL: str = "INFO"
+    ALGORITHM: str = "HS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
+
+    class Config:
+        env_file = ".env"
+
+
+settings = Settings()
+
+engine = create_engine(settings.DATABASE_URL, pool_pre_ping=True)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+Base = declarative_base()
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()