feat: add all application source code

- apps/api: FastAPI backend with Dockerfile
- apps/web: Next.js frontend with Dockerfile
- apps/sensor: Signal collection agent
- packages: shared packages

Co-Authored-By: Claude <noreply@anthropic.com>

apps/api/src/db/__init__.py

@@ -0,0 +1,22 @@
+"""
+AWOOOI Database Module
+======================
+CTO-201: SQLAlchemy + aiosqlite (PostgreSQL-ready)
+
+架構設計原則：
+- 使用 SQLAlchemy 2.0 async 風格
+- Schema 與 PostgreSQL 100% 相容
+- 一行代碼切換資料庫後端
+"""
+
+from src.db.base import Base, get_db, init_db
+from src.db.models import ApprovalRecord, AuditLog, IncidentRecord
+
+__all__ = [
+    "Base",
+    "get_db",
+    "init_db",
+    "ApprovalRecord",
+    "AuditLog",
+    "IncidentRecord",
+]