feat: T03 backend core – FastAPI + DB models + Equipment API + Redis cache + health + tests

- FastAPI app with CORS, lifespan handlers
- Pydantic Settings config (DB, Redis, CORS, SMTP, JWT, Rentman)
- SQLAlchemy async engine + session (DeclarativeBase)
- 6 DB models: EquipmentCache, RentalRequest, RentalRequestItem, Contact, AdminUser, SyncLog
- Pydantic schemas: EquipmentItem, EquipmentDetail, PaginatedEquipment, ContactCreate, ContactResponse
- Redis cache helper: set/get/delete_pattern, rate limiting, equipment key builders
- Equipment router: list (search/category/sort/pagination), detail, categories – all cached
- Contact router: POST with Pydantic validation + rate limiting (5/min)
- Health router: GET /api/health with DB + Redis status
- 28 pytest tests (all pass, 90% coverage)
- Dockerfile, requirements.txt, pytest.ini, test_report.md

backend/app/models/sync_log.py

@@ -0,0 +1,27 @@
+"""SyncLog SQLAlchemy model."""
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, Index, Integer, String, Text, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.database import Base
+
+
+class SyncLog(Base):
+    """Log entry for equipment sync operations."""
+
+    __tablename__ = "sync_log"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    sync_type: Mapped[str] = mapped_column(String(32), default="equipment", nullable=False)
+    status: Mapped[str] = mapped_column(String(32), nullable=False)
+    items_processed: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
+    items_failed: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
+    error_message: Mapped[str | None] = mapped_column(Text, nullable=True)
+    started_at: Mapped[datetime] = mapped_column(server_default=func.now(), nullable=False)
+    completed_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+
+    __table_args__ = (
+        Index("idx_sync_log_started", "started_at"),
+    )