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/routes/notifications.py

@@ -0,0 +1,73 @@
+"""
+Notification Endpoints
+"""
+
+from datetime import datetime
+from typing import Literal
+from uuid import UUID, uuid4
+
+from fastapi import APIRouter
+from pydantic import BaseModel
+
+router = APIRouter()
+
+
+class NotificationChannel(BaseModel):
+    id: str
+    type: Literal["telegram", "slack", "line", "email", "discord", "webhook"]
+    name: str
+    enabled: bool
+
+
+class NotificationRequest(BaseModel):
+    channel_id: str
+    message: str
+    template_id: str | None = None
+    variables: dict | None = None
+    priority: Literal["low", "normal", "high", "urgent"] = "normal"
+
+
+class NotificationResult(BaseModel):
+    id: UUID
+    status: Literal["queued", "sent", "failed"]
+    sent_at: datetime | None = None
+    error: str | None = None
+
+
+# Mock channels
+MOCK_CHANNELS: list[NotificationChannel] = [
+    NotificationChannel(
+        id="telegram-ops",
+        type="telegram",
+        name="Ops Team",
+        enabled=True,
+    ),
+    NotificationChannel(
+        id="slack-alerts",
+        type="slack",
+        name="Alerts Channel",
+        enabled=True,
+    ),
+    NotificationChannel(
+        id="email-oncall",
+        type="email",
+        name="On-Call Email",
+        enabled=True,
+    ),
+]
+
+
+@router.get("/channels", response_model=list[NotificationChannel])
+async def list_notification_channels() -> list[NotificationChannel]:
+    """列出通知頻道"""
+    return MOCK_CHANNELS
+
+
+@router.post("/send", response_model=NotificationResult, status_code=202)
+async def send_notification(request: NotificationRequest) -> NotificationResult:
+    """發送通知"""
+    # TODO: 實際發送通知
+    return NotificationResult(
+        id=uuid4(),
+        status="queued",
+    )