refactor(alerts/ui): rewrite Rules list with DataTable + Dropdown + ConfirmDialog

Replaces raw <table> with DataTable, raw <select> promote control with
DS Dropdown, and native confirm() delete with ConfirmDialog. Adds DS
EmptyState with CTA for the no-rules case. Uses SectionHeader's
action slot instead of ad-hoc flex wrapper.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/src/pages/Alerts/RulesListPage.tsx

@@ -1,5 +1,11 @@
+import { useState } from 'react';
 import { Link, useNavigate } from 'react-router';
-import { Button, SectionHeader, Toggle, useToast, Badge } from '@cameleer/design-system';
+import { FilePlus } from 'lucide-react';
+import {
+  Button, SectionHeader, Toggle, useToast, Badge, DataTable,
+  EmptyState, Dropdown, ConfirmDialog,
+} from '@cameleer/design-system';
+import type { Column } from '@cameleer/design-system';
 import { PageLoader } from '../../components/PageLoader';
 import { SeverityBadge } from '../../components/SeverityBadge';
 import {
@@ -10,7 +16,8 @@ import {
 } from '../../api/queries/alertRules';
 import { useEnvironments } from '../../api/queries/admin/environments';
 import { useSelectedEnv } from '../../api/queries/alertMeta';
-import sectionStyles from '../../styles/section-card.module.css';
+import tableStyles from '../../styles/table-section.module.css';
+import css from './alerts-page.module.css';
 
 export default function RulesListPage() {
   const navigate = useNavigate();
@@ -21,28 +28,32 @@ export default function RulesListPage() {
   const deleteRule = useDeleteAlertRule();
   const { toast } = useToast();
 
+  const [pendingDelete, setPendingDelete] = useState<AlertRuleResponse | null>(null);
+
   if (isLoading) return <PageLoader />;
-  if (error) return <div>Failed to load rules: {String(error)}</div>;
+  if (error) return <div className={css.page}>Failed to load rules: {String(error)}</div>;
 
   const rows = rules ?? [];
   const otherEnvs = (envs ?? []).filter((e) => e.slug !== env);
 
   const onToggle = async (r: AlertRuleResponse) => {
     try {
-      await setEnabled.mutateAsync({ id: r.id, enabled: !r.enabled });
+      await setEnabled.mutateAsync({ id: r.id!, enabled: !r.enabled });
       toast({ title: r.enabled ? 'Disabled' : 'Enabled', description: r.name, variant: 'success' });
     } catch (e) {
       toast({ title: 'Toggle failed', description: String(e), variant: 'error' });
     }
   };
 
-  const onDelete = async (r: AlertRuleResponse) => {
-    if (!confirm(`Delete rule "${r.name}"? Fired alerts are preserved via rule_snapshot.`)) return;
+  const confirmDelete = async () => {
+    if (!pendingDelete) return;
     try {
-      await deleteRule.mutateAsync(r.id);
-      toast({ title: 'Deleted', description: r.name, variant: 'success' });
+      await deleteRule.mutateAsync(pendingDelete.id!);
+      toast({ title: 'Deleted', description: pendingDelete.name, variant: 'success' });
     } catch (e) {
       toast({ title: 'Delete failed', description: String(e), variant: 'error' });
+    } finally {
+      setPendingDelete(null);
     }
   };
 
@@ -50,66 +61,103 @@ export default function RulesListPage() {
     navigate(`/alerts/rules/new?promoteFrom=${env}&ruleId=${r.id}&targetEnv=${targetEnvSlug}`);
   };
 
+  const columns: Column<AlertRuleResponse & { id: string }>[] = [
+    {
+      key: 'name', header: 'Name',
+      render: (_, r) => <Link to={`/alerts/rules/${r.id}`}>{r.name}</Link>,
+    },
+    {
+      key: 'conditionKind', header: 'Kind', width: '160px',
+      render: (_, r) => <Badge label={r.conditionKind ?? ''} color="auto" variant="outlined" />,
+    },
+    {
+      key: 'severity', header: 'Severity', width: '110px',
+      render: (_, r) => <SeverityBadge severity={r.severity!} />,
+    },
+    {
+      key: 'enabled', header: 'Enabled', width: '90px',
+      render: (_, r) => (
+        <Toggle
+          checked={!!r.enabled}
+          onChange={() => onToggle(r)}
+          disabled={setEnabled.isPending}
+        />
+      ),
+    },
+    {
+      key: 'targets', header: 'Targets', width: '90px',
+      render: (_, r) => String(r.targets?.length ?? 0),
+    },
+    {
+      key: 'actions', header: '', width: '220px',
+      render: (_, r) => (
+        <div style={{ display: 'flex', gap: 'var(--space-sm)', justifyContent: 'flex-end' }}>
+          {otherEnvs.length > 0 && (
+            <Dropdown
+              trigger={<Button variant="ghost" size="sm">Promote to ▾</Button>}
+              items={otherEnvs.map((e) => ({
+                label: e.slug,
+                onClick: () => onPromote(r, e.slug),
+              }))}
+            />
+          )}
+          <Button variant="ghost" size="sm" onClick={() => setPendingDelete(r)} disabled={deleteRule.isPending}>
+            Delete
+          </Button>
+        </div>
+      ),
+    },
+  ];
+
   return (
-    <div style={{ padding: 16 }}>
-      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 16 }}>
-        <SectionHeader>Alert rules</SectionHeader>
-        <Link to="/alerts/rules/new">
-          <Button variant="primary">New rule</Button>
-        </Link>
-      </div>
-      <div className={sectionStyles.section}>
-        {rows.length === 0 ? (
-          <p>No rules yet. Create one to start evaluating alerts for this environment.</p>
-        ) : (
-          <table style={{ width: '100%', borderCollapse: 'collapse' }}>
-            <thead>
-              <tr>
-                <th style={{ textAlign: 'left' }}>Name</th>
-                <th style={{ textAlign: 'left' }}>Kind</th>
-                <th style={{ textAlign: 'left' }}>Severity</th>
-                <th style={{ textAlign: 'left' }}>Enabled</th>
-                <th style={{ textAlign: 'left' }}>Targets</th>
-                <th></th>
-              </tr>
-            </thead>
-            <tbody>
-              {rows.map((r) => (
-                <tr key={r.id}>
-                  <td><Link to={`/alerts/rules/${r.id}`}>{r.name}</Link></td>
-                  <td><Badge label={r.conditionKind} color="auto" variant="outlined" /></td>
-                  <td><SeverityBadge severity={r.severity} /></td>
-                  <td>
-                    <Toggle
-                      checked={r.enabled}
-                      onChange={() => onToggle(r)}
-                      disabled={setEnabled.isPending}
-                    />
-                  </td>
-                  <td>{r.targets.length}</td>
-                  <td style={{ display: 'flex', gap: 8, justifyContent: 'flex-end' }}>
-                    {otherEnvs.length > 0 && (
-                      <select
-                        value=""
-                        onChange={(e) => { if (e.target.value) onPromote(r, e.target.value); }}
-                        aria-label={`Promote ${r.name} to another env`}
-                      >
-                        <option value="">Promote to ▾</option>
-                        {otherEnvs.map((e) => (
-                          <option key={e.slug} value={e.slug}>{e.slug}</option>
-                        ))}
-                      </select>
-                    )}
-                    <Button variant="secondary" onClick={() => onDelete(r)} disabled={deleteRule.isPending}>
-                      Delete
-                    </Button>
-                  </td>
-                </tr>
-              ))}
-            </tbody>
-          </table>
-        )}
+    <div className={css.page}>
+      <div className={css.toolbar}>
+        <SectionHeader
+          action={
+            <Link to="/alerts/rules/new">
+              <Button variant="primary">New rule</Button>
+            </Link>
+          }
+        >
+          Alert rules
+        </SectionHeader>
       </div>
+
+      {rows.length === 0 ? (
+        <EmptyState
+          icon={<FilePlus size={32} />}
+          title="No alert rules"
+          description="Create one to start evaluating alerts for this environment."
+          action={
+            <Link to="/alerts/rules/new">
+              <Button variant="primary">Create rule</Button>
+            </Link>
+          }
+        />
+      ) : (
+        <div className={tableStyles.tableSection}>
+          <DataTable<AlertRuleResponse & { id: string }>
+            columns={columns}
+            data={rows as (AlertRuleResponse & { id: string })[]}
+            flush
+          />
+        </div>
+      )}
+
+      <ConfirmDialog
+        open={!!pendingDelete}
+        onClose={() => setPendingDelete(null)}
+        onConfirm={confirmDelete}
+        title="Delete alert rule?"
+        message={
+          pendingDelete
+            ? `Delete rule "${pendingDelete.name}"? Fired alerts are preserved via rule_snapshot.`
+            : ''
+        }
+        confirmText="Delete"
+        variant="danger"
+        loading={deleteRule.isPending}
+      />
     </div>
   );
 }