feat: interactive network map, IOC highlighting, AUP hunt selector, type filters

- NetworkMap: hunt-scoped force-directed graph with click-to-inspect popover
- NetworkMap: zoom/pan (wheel, drag, buttons), viewport transform
- NetworkMap: clickable IP/Host/Domain/URL legend chips to filter node types
- NetworkMap: brighter colors, 20% smaller nodes
- DatasetViewer: IOC columns highlighted with colored headers + cell tinting
- AUPScanner: hunt dropdown replacing dataset checkboxes, auto-select all
- Rename 'Social Media (Personal)' theme to 'Social Media' with DB migration
- Fix /api/hunts timeout: Dataset.rows lazy='noload' (was selectin cascade)
- Add OS column mapping to normalizer
- Full backend services, DB models, alembic migrations, new routes
- New components: Dashboard, HuntManager, FileUpload, NetworkMap, etc.
- Docker Compose deployment with nginx reverse proxy

backend/app/db/engine.py

@@ -0,0 +1,54 @@
+"""Database engine, session factory, and base model.
+
+Uses async SQLAlchemy with aiosqlite for local dev and asyncpg for production PostgreSQL.
+"""
+
+from sqlalchemy.ext.asyncio import (
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.DEBUG,
+    future=True,
+)
+
+async_session_factory = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    """Base class for all ORM models."""
+    pass
+
+
+async def get_db() -> AsyncSession:  # type: ignore[misc]
+    """FastAPI dependency that yields an async DB session."""
+    async with async_session_factory() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()
+
+
+async def init_db() -> None:
+    """Create all tables (for dev / first-run). In production use Alembic."""
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+
+async def dispose_db() -> None:
+    """Dispose of the engine connection pool."""
+    await engine.dispose()