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/workers/__init__.py

@@ -0,0 +1,26 @@
+"""
+AWOOOI Workers - 背景處理模組
+=============================
+Phase 6.1: Event Bus Workers
+
+所有非同步背景任務的統一入口。
+
+統帥鐵律:
+- Workers 只消費，不直接接收外部請求
+- 所有 Worker 在 Lifespan 中啟動/關閉
+- 失敗重試有上限，避免無限循環
+"""
+
+from src.workers.signal_worker import (
+    SignalWorker,
+    get_signal_worker,
+    init_signal_worker,
+    close_signal_worker,
+)
+
+__all__ = [
+    "SignalWorker",
+    "get_signal_worker",
+    "init_signal_worker",
+    "close_signal_worker",
+]