feat(tenant): hide setup/settings surfaces when HELIX_SETUP_MANAGED

Ramaiah's product team owns their setup; end-user admins shouldn't see a dead-end Settings nav + Resume Setup banner. Flag is read from /api/config/ui-flags at app boot.

- use-ui-flags: module-scoped cache + useUiFlags hook + getUiFlags
  helper for non-component callers
- main.tsx: /setup redirects when managed; RequireSelfServeSetup
  guard blocks /settings/*
- resume-setup-banner: suppressed when managed
- login.tsx: skip first-run /setup redirect when managed
- settings.tsx: remove orphan popup-modal scaffolding left over
  from an earlier 'contact product team' approach
- section-card: support onClick-or-href (kept for future use)

src/components/setup/section-card.tsx

@@ -10,27 +10,32 @@ type SectionCardProps = {
     description: string;
     icon: any;
     iconColor?: string;
-    href: string;
+    // Either navigate (href) OR intercept the click (onClick). When onClick
+    // is provided, href is ignored and the card renders as a button. Used
+    // while self-serve setup is disabled — all clicks go through a
+    // "contact product team" modal in settings.tsx.
+    href?: string;
+    onClick?: () => void;
     status?: SectionStatus;
 };
 
 // Settings hub card. Each card represents one setup-able section (Branding,
-// Clinics, Doctors, Team, Telephony, AI, Widget, Rules) and links to its
-// dedicated page. The status badge mirrors the wizard's setup-state so an
-// admin can see at a glance which sections still need attention.
+// Clinics, Doctors, Team, Telephony, AI, Widget, Rules) and either links to
+// its dedicated page or triggers a parent-owned callback.
 export const SectionCard = ({
     title,
     description,
     icon,
     iconColor = 'text-brand-primary',
     href,
+    onClick,
     status = 'unknown',
 }: SectionCardProps) => {
-    return (
-        <Link
-            to={href}
-            className="group block rounded-xl border border-secondary bg-primary p-5 shadow-xs transition hover:border-brand hover:shadow-md"
-        >
+    const className = cx(
+        'group block w-full text-left rounded-xl border border-secondary bg-primary p-5 shadow-xs transition hover:border-brand hover:shadow-md',
+    );
+    const body = (
+        <>
             <div className="flex items-start justify-between gap-4">
                 <div className="flex items-start gap-4">
                     <div className="flex size-11 shrink-0 items-center justify-center rounded-lg bg-secondary">
@@ -62,6 +67,19 @@ export const SectionCard = ({
                     )}
                 </div>
             )}
+        </>
+    );
+
+    if (onClick) {
+        return (
+            <button type="button" onClick={onClick} className={className}>
+                {body}
+            </button>
+        );
+    }
+    return (
+        <Link to={href ?? '#'} className={className}>
+            {body}
         </Link>
     );
 };