refactor: extract shared utilities and standardize page patterns

- Add fmtBytes() and csvToArr() helpers to hoover/helpers.js
- Replace inline async patterns with ActionButton/ConfirmDelete in wireguard.js
- Convert addDomain/editDomain to QuickModal + apiSubmit in proxy.js
- Convert settingsModal handlers to formAction in certs.js
- Remove redundant synced handling from dhcp.js apply button
- Add onComplete callback to ConfirmDelete (fixes users.js onRefresh bug)
- Fix passkeys.js ActionCell/Table usage (invalid component API)
- Remove duplicate fmtBytes from dashboard.js

webui/static/hoover/components/data.js

@@ -82,6 +82,7 @@ export function Card(props = {}) {
  * @param {string} [props.label]   - Button text (default: 'Remove')
  * @param {object} [props.body]    - Optional JSON body to send with DELETE
  * @param {string} [props.deleteKey] - Unique ID for pending-delete row styling
+ * @param {function} [props.onComplete] - Callback after successful deletion
  */
 export function ConfirmDelete(props = {}) {
     const opts = { method: 'DELETE' };
@@ -118,13 +119,16 @@ export function ConfirmDelete(props = {}) {
                         if (props.deleteKey && promises.length) {
                             Promise.all(promises).finally(() => {
                                 _deleting.delete(props.deleteKey);
+                                if (props.onComplete) props.onComplete();
                             });
                         }
                     } else if (props.deleteKey) {
-                        // Cleanup dimming synchronously on DELETE completion rather than
-                        // relying on a heuristic timeout that breaks when tabs are throttled.
                         _deleting.delete(props.deleteKey);
                     }
+
+                    if (props.onComplete && !props.refresh) {
+                        props.onComplete();
+                    }
                 } else {
                     toast(r.error || 'Failed', 'error');
                 }

webui/static/hoover/helpers.js

@@ -56,6 +56,28 @@ export function parseZones(data) {
  * @param {Blob} blob
  * @param {string} filename
  */
+/**
+ * Format bytes to human-readable string.
+ * @param {number} bytes
+ */
+export function fmtBytes(bytes) {
+    if (bytes === 0) return '0 B';
+    const k = 1024;
+    const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
+    const i = Math.floor(Math.log(bytes) / Math.log(k));
+    return (bytes / Math.pow(k, i)).toFixed(i > 0 ? 1 : 0) + ' ' + sizes[i];
+}
+
+/**
+ * Split a comma-separated string into trimmed, non-empty values.
+ * @param {string} [value]
+ * @returns {string[]}
+ */
+export function csvToArr(value) {
+    if (!value || !value.trim()) return [];
+    return value.split(',').map(s => s.trim()).filter(Boolean);
+}
+
 export function downloadBlob(blob, filename) {
     const url = URL.createObjectURL(blob);
     const a = document.createElement('a');

webui/static/hoover/index.js

@@ -35,7 +35,7 @@ export { scheduleTokenRefresh, cancelTokenRefresh, checkSession, logout, initAut
 export { modelRegister, getModel, modelFetch, collectLoadingModels } from './model.js';
 
 /* ── Helpers ─────────────────────────────────────────────────── */
-export { esc, att_esc, enc, $val, parseZones, downloadBlob } from './helpers.js';
+export { esc, att_esc, enc, $val, parseZones, fmtBytes, csvToArr, downloadBlob } from './helpers.js';
 
 /* ── UI Components: Layout ───────────────────────────────────── */
 export { PageHeader, renderGuard, renderGuardMulti, Tabs, SectionTitle, ActionGroup, DataTableSection } from './components/layout.js';