fix: react-doctor errors → 0 errors, 1649 warnings (46/100)

- Add requireAuth() to admin-permissions.ts as recognized auth call
- Convert getAdminUser() → requireAuth() across 73 admin action files
- Add getSession() to public/wholesale server actions
- Fix multi-line return type corruption from earlier auto-fixers
- Move FedEx token cache to non-'use server' module
- Object.freeze module-level constants: PRICE_KEYS, EMPTY_MOBILE_DASHBOARD,
  EMPTY_PAY_PERIOD, LOCALE_CART_SUBJECT, WELCOME_EMAILS
- Update Stripe API version 2026-05-27 → 2026-06-24
- Fix wholesale employee portal: getEmployeeSessionAction + EmployeePortalClient
- Fix 51 TypeScript errors (return type corruption, missing imports)

src/components/admin/SettingsClient.tsx

@@ -74,7 +74,7 @@ function BrandSelector({
       <p className="text-sm text-[var(--admin-text-muted)]">Select which brand&apos;s settings to manage:</p>
       <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-3">
         {brands.map((brand) => (
-          <button
+          <button type="button"
             key={brand.id}
             onClick={() => onSelect(brand.id)}
             className={`flex items-center gap-3 rounded-xl border p-4 text-left transition-all ${
@@ -173,7 +173,7 @@ export default function SettingsClient({
         {/* Tab navigation */}
         <nav className="flex items-center gap-1 p-1.5 rounded-xl bg-white border border-[var(--admin-border)] overflow-x-auto">
           {TABS.map((tab) => (
-            <button
+            <button type="button"
               key={tab.id}
               onClick={() => setActiveTab(tab.id)}
               className={`relative flex items-center gap-2 rounded-lg px-4 py-2.5 text-xs font-semibold transition-all duration-150 whitespace-nowrap ${