feat: add system metrics dashboard with resource monitoring

- Add system metrics endpoint (CPU load, memory, swap, network traffic)
- Collect metrics from /proc and /sys (no subprocess required)
- Overhaul dashboard to pull from per-subsystem models
- Remove deprecated /status/all monolithic endpoint
- Improve networkd import to handle optional priority prefix
- Fix CSS duplicate .grid-4 rule and unused dashboard imports

daemon/iface.py

@@ -155,12 +155,12 @@ GET_LOGS_APP: Endpoint = _ep("GET", "/logs/app")
 
 # ---- Server infra (not going through client) ----
 GET_HEALTH: Endpoint = _ep("GET", "/health")
-GET_STATUS_ALL: Endpoint = _ep("GET", "/status/all")
 POST_STATUS_REFRESH: Endpoint = _ep("POST", "/status/refresh")
 GET_WS: Endpoint = _ep("GET", "/ws")
 POST_BATCH: Endpoint = _ep("POST", "/batch")
 GET_STATUS_PENDING: Endpoint = _ep("GET", "/status/pending")
 POST_STATUS_APPLY_ALL: Endpoint = _ep("POST", "/status/apply-all")
+GET_SYSTEM_METRICS: Endpoint = _ep("GET", "/system/metrics")
 
 # Collect all endpoint module-level constants for __all__ verification
 _all_endpoints = [