feat: add Synology NAS, Home Assistant monitoring, multi-channel notifications

New tabs:
- Synology NAS: CPU, RAM, temp, volumes, VMs, Docker containers
- Home Assistant: sensors, automations, persons, climate, battery, doors

New features:
- Personalized PC agent download with custom name
- Notification settings: per-category Telegram/Email/WhatsApp toggles
- Email via SMTP, WhatsApp via CallMeBot API
- Test notification buttons for each channel
- Unified notifier replaces direct Telegram calls in alerter

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

server/api/ha.py

@@ -0,0 +1,115 @@
+"""Home Assistant monitoring API endpoints."""
+
+import json
+from datetime import datetime
+from typing import Dict
+
+from fastapi import APIRouter, Request, Depends
+
+from server.auth import require_auth
+from server.config import DATA_DIR
+
+router = APIRouter(prefix="/api/ha", tags=["homeassistant"])
+
+# In-memory cache
+ha_metrics: Dict[str, dict] = {}
+
+HA_FILE = DATA_DIR / "homeassistant.json"
+
+
+def _load_ha():
+    if HA_FILE.exists():
+        with open(HA_FILE) as f:
+            return json.load(f)
+    return []
+
+
+def _save_ha(data):
+    with open(HA_FILE, "w") as f:
+        json.dump(data, f, indent=2, ensure_ascii=False)
+
+
+@router.get("/list")
+async def ha_list(request: Request, user: str = Depends(require_auth)):
+    """List all Home Assistant instances with metrics."""
+    instances = _load_ha()
+    for inst in instances:
+        name = inst["name"]
+        if name in ha_metrics:
+            inst["metrics"] = ha_metrics[name]
+    return instances
+
+
+@router.post("/add")
+async def ha_add(request: Request, user: str = Depends(require_auth)):
+    """Add a Home Assistant instance."""
+    body = await request.json()
+    name = body.get("name", "").strip()
+    url = body.get("url", "").strip()
+    token = body.get("token", "").strip()
+
+    if not name or not url or not token:
+        return {"status": "error", "detail": "name, url, and token required"}
+
+    instances = _load_ha()
+    instance = {
+        "name": name,
+        "url": url,
+        "token": token,
+        "added": datetime.now().isoformat(),
+    }
+    instances.append(instance)
+    _save_ha(instances)
+
+    return {"status": "ok"}
+
+
+@router.delete("/{name}")
+async def ha_delete(name: str, request: Request, user: str = Depends(require_auth)):
+    """Remove a Home Assistant instance."""
+    instances = _load_ha()
+    instances = [i for i in instances if i["name"] != name]
+    _save_ha(instances)
+    ha_metrics.pop(name, None)
+    return {"status": "ok"}
+
+
+@router.post("/refresh/{name}")
+async def ha_refresh(name: str, request: Request, user: str = Depends(require_auth)):
+    """Force refresh metrics for a Home Assistant instance."""
+    from server.services.ha_client import HomeAssistantClient
+
+    instances = _load_ha()
+    inst = next((i for i in instances if i["name"] == name), None)
+    if not inst:
+        return {"status": "error", "detail": "instance not found"}
+
+    client = HomeAssistantClient(url=inst["url"], token=inst["token"])
+    try:
+        metrics = await client.collect_all_metrics()
+        metrics["last_updated"] = datetime.now().isoformat()
+        ha_metrics[name] = metrics
+        return {"status": "ok", "metrics": metrics}
+    except Exception as e:
+        return {"status": "error", "detail": str(e)}
+
+
+@router.post("/refresh-all")
+async def ha_refresh_all(request: Request, user: str = Depends(require_auth)):
+    """Refresh metrics for all Home Assistant instances."""
+    from server.services.ha_client import HomeAssistantClient
+
+    instances = _load_ha()
+    results = []
+
+    for inst in instances:
+        client = HomeAssistantClient(url=inst["url"], token=inst["token"])
+        try:
+            metrics = await client.collect_all_metrics()
+            metrics["last_updated"] = datetime.now().isoformat()
+            ha_metrics[inst["name"]] = metrics
+            results.append({"name": inst["name"], "online": metrics["online"]})
+        except Exception as e:
+            results.append({"name": inst["name"], "online": False, "error": str(e)})
+
+    return {"status": "ok", "results": results}