Add system memory monitoring, Bedrock support, and Discord integrations

- Add CPU/GPU memory monitoring endpoint and frontend widget
- Add Amazon Bedrock model support (API key / inference profiles) plus model selector entries
- Add Discord weather/laundry notification job (JMA forecast + LLM-generated message)
- Add Discord bot that replies to mentions via the configured LLM, with weather-aware context
- Add scheduled "useless tips" job with separate webhook and quiet-hours skip
- Switch FastAPI startup to lifespan handler, log viewer, markdown rendering, and toast UI additions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/api/system.py

@@ -0,0 +1,63 @@
+from fastapi import APIRouter
+import psutil
+from pydantic import BaseModel
+
+from app.core.scheduler import send_useless_tip, send_weather_laundry_notification
+
+router = APIRouter(prefix="/api/system", tags=["system"])
+
+
+class MemoryStats(BaseModel):
+    cpu_percent: float
+    memory_percent: float
+    memory_used_mb: float
+    memory_total_mb: float
+    gpu_memory_used_mb: float | None = None
+    gpu_memory_total_mb: float | None = None
+    gpu_memory_percent: float | None = None
+
+
+@router.get("/memory", response_model=MemoryStats)
+async def get_memory_stats():
+    """CPU と GPU のメモリ使用状況を返す"""
+    # CPU/メモリ情報
+    cpu_percent = psutil.cpu_percent(interval=0.1)
+    memory = psutil.virtual_memory()
+
+    stats = {
+        "cpu_percent": cpu_percent,
+        "memory_percent": memory.percent,
+        "memory_used_mb": memory.used / (1024 * 1024),
+        "memory_total_mb": memory.total / (1024 * 1024),
+    }
+
+    # GPU 情報（オプション）
+    try:
+        import pynvml
+        pynvml.nvmlInit()
+        device_count = pynvml.nvmlDeviceGetCount()
+        if device_count > 0:
+            handle = pynvml.nvmlDeviceGetHandleByIndex(0)
+            mem_info = pynvml.nvmlDeviceGetMemoryInfo(handle)
+            stats["gpu_memory_used_mb"] = mem_info.used / (1024 * 1024)
+            stats["gpu_memory_total_mb"] = mem_info.total / (1024 * 1024)
+            stats["gpu_memory_percent"] = (mem_info.used / mem_info.total) * 100
+        pynvml.nvmlShutdown()
+    except Exception:
+        pass
+
+    return MemoryStats(**stats)
+
+
+@router.post("/weather-notify/test")
+async def test_weather_notify():
+    """天気予報→Discord通知を手動で即時実行する（動作確認用）"""
+    await send_weather_laundry_notification()
+    return {"status": "sent"}
+
+
+@router.post("/useless-tip/test")
+async def test_useless_tip():
+    """どうでもいいtips→Discord通知を手動で即時実行する（動作確認用）"""
+    await send_useless_tip()
+    return {"status": "sent"}