feat: add stats polling interval + correct health polling default to Settings

- Add 'Stats Polling Interval' (default 30s) field to Health -> Configure ->
  Global Settings, alongside the existing 'Polling Interval' which is now
  relabeled 'Health Check Polling Interval' with the correct default of 60s.
- Persist/load statsPollingInterval via the health-settings localStorage key
  (same mechanism as the other settings).
- Wire the persisted statsPollingInterval into DC.POLL.STATS so the resource
  monitor / monitoring widgets honor the configured cadence (seconds -> ms).
- Update the setup wizard disk-safety 'Recommended after setup' list to
  mention both polling intervals.
- Rebuild dist bundles (core.js, features.js) and bump service-worker cache.

status/js/globals.js

@@ -1,10 +1,28 @@
 // ===== DASHBOARD CONSTANTS =====
+// Honor persisted health retention settings for polling cadences so the
+// Settings → Health → Global Settings panel actually takes effect. The
+// STATS interval (resource/container stat sampling) is driven from the
+// user-configurable statsPollingInterval. HEALTH is the lightweight card
+// badge refresh and stays at its fast default unless overridden.
+(function applyHealthPollingSettings() {
+  try {
+    var raw = (typeof localStorage !== 'undefined' && localStorage.getItem('dashcaddy-health-settings')) || null;
+    if (raw) {
+      var s = JSON.parse(raw);
+      // values are stored in seconds; DC.POLL expects milliseconds
+      if (s.statsPollingInterval && s.statsPollingInterval >= 5 && s.statsPollingInterval <= 3600) {
+        window.__DC_STATS_OVERRIDE = s.statsPollingInterval * 1000;
+      }
+    }
+  } catch (_) { /* ignore — fall back to defaults below */ }
+})();
+
 const DC = {
   NAME: 'DashCaddy',
   POLL: {
     DASHBOARD:  10000,   // 10s — main refreshAll interval
     LOGS:       3000,    // 3s  — log viewer updates
-    STATS:      5000,    // 5s  — resource monitor refresh
+    STATS:      (typeof window !== 'undefined' && window.__DC_STATS_OVERRIDE) || 5000,   // 5s default — resource monitor refresh (overridable via Settings → Health)
     WEATHER:    600000,  // 10m — weather widget refresh
     HEALTH:     1000,    // 1s  — card health badge refresh
     DEPLOY_SSL: 5000,    // 5s  — SSL cert check during deploy