feat(residential-toggle): port-level module gate for Residential

Adds a `residential_module_enabled` port setting (default ON) that
hides/disables the entire Residential surface when an admin turns it
off, mirroring the Tenancies / Invoices / Expenses module-toggle
pattern. Disabling is a soft hide — residential clients/interests are
preserved and reappear on re-enable.

Surfaces gated:
- Route guard: new residential/layout.tsx renders ModuleDisabledPage
  (covers all 5 residential pages)
- Sidebar "Residential" section + mobile more-sheet tile (SSR-resolved
  residentialModuleByPort threaded layout → app-shell → sidebar)
- Global search: residential client/interest buckets early-return at
  the shared chokepoint so disabled-port records don't dead-end
- Public intake: /api/public/residential-inquiries 404s when off
- Admin Switch in settings-manager (writes via settings PUT)

Service TDD'd (residential-module.test.ts, 6 tests) plus a
disabled-port rejection test on the public endpoint. tsc + lint clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/layout/app-shell.tsx

@@ -32,6 +32,10 @@ interface AppShellProps {
    *  + How-to-upload-receipts sidebar entries SSR-side. Defaults to
    *  true so existing ports keep the feature. */
   expensesModuleByPort: Record<string, boolean>;
+  /** Per-port `residential_module_enabled` resolution. Gates the
+   *  "Residential" sidebar section + mobile entry SSR-side. Defaults to
+   *  true so existing ports keep the feature. */
+  residentialModuleByPort: Record<string, boolean>;
   /**
    * Server-rendered form-factor hint (from the request User-Agent). The
    * shell mounts the matching tree on first render so we never paint the
@@ -96,6 +100,7 @@ export function AppShell({
   portLogoUrls,
   tenanciesModuleByPort,
   expensesModuleByPort,
+  residentialModuleByPort,
   initialFormFactor,
   children,
 }: AppShellProps) {
@@ -104,6 +109,7 @@ export function AppShell({
   const [searchOpen, setSearchOpen] = useState(false);
   const [tabletSidebarOpen, setTabletSidebarOpen] = useState(false);
   const currentPortSlug = useUIStore((s) => s.currentPortSlug);
+  const currentPortId = useUIStore((s) => s.currentPortId);
   const logoUrl = currentPortSlug ? portLogoUrls[currentPortSlug] : null;
 
   useEffect(() => {
@@ -149,8 +155,15 @@ export function AppShell({
     portLogoUrls,
     tenanciesModuleByPort,
     expensesModuleByPort,
+    residentialModuleByPort,
   };
 
+  // Resolve the current port's residential flag for the mobile More sheet
+  // (the sidebar resolves its own copy internally from the by-port map).
+  const residentialModuleEnabled = currentPortId
+    ? (residentialModuleByPort[currentPortId] ?? true)
+    : true;
+
   // Chrome subtree per tier.
   let chrome: ReactNode = null;
   if (isMobile) {
@@ -177,7 +190,11 @@ export function AppShell({
         onMoreClick={() => setMoreOpen(true)}
         onSearchClick={() => setSearchOpen(true)}
       />
-      <MoreSheet open={moreOpen} onOpenChange={setMoreOpen} />
+      <MoreSheet
+        open={moreOpen}
+        onOpenChange={setMoreOpen}
+        residentialModuleEnabled={residentialModuleEnabled}
+      />
       <MobileSearchOverlay open={searchOpen} onOpenChange={setSearchOpen} />
     </>
   ) : null;