fix(audit-wave-9): standardize on Sheet for previews; doctrine in CLAUDE.md

Swap the one outlier (client-interests-tab.tsx) from Vaul Drawer to
Sheet side=right so every detail-preview surface uses the same
primitive. Document the doctrine: Sheet for side panels on both desktop
and mobile; Vaul Drawer reserved for mobile-only bottom-sheet UX
(currently just MoreSheet).

Closes ui/ux M11.

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

src/app/(dashboard)/[portSlug]/expenses/scan/page.tsx

@@ -19,7 +19,7 @@ import {
   SelectValue,
 } from '@/components/ui/select';
 import { apiFetch } from '@/lib/api/client';
-import { EXPENSE_CATEGORIES } from '@/lib/constants';
+import { EXPENSE_CATEGORIES, formatEnum } from '@/lib/constants';
 
 interface ScanResult {
   establishment: string | null;
@@ -345,7 +345,7 @@ export default function ScanReceiptPage() {
                 <SelectContent>
                   {EXPENSE_CATEGORIES.map((cat) => (
                     <SelectItem key={cat} value={cat}>
-                      {cat.replace(/_/g, ' ').replace(/\b\w/g, (l) => l.toUpperCase())}
+                      {formatEnum(cat)}
                     </SelectItem>
                   ))}
                 </SelectContent>