feat(nav): gate the Insights destination on the insights module

Mark the top-level `/insights` nav destination `requiresModule: "insights"`
so it drops from both bars when the account has the insights module off,
mirroring mood / labs / coach / achievements. The bottom-nav pinned
`/insights` as a fixed primary slot regardless of the module map; it now
filters that slot through the same per-user map the More hub honours
(fail-open on a missing key / unloaded /me payload). A disabled insights
module is hidden everywhere — the primary-slot filter keeps it out of the
More hub too, so it is hidden, not relocated.

Extend the nav-model + bottom-nav tests with insights on/off coverage.

src/components/layout/__tests__/bottom-nav.test.tsx

@@ -150,6 +150,27 @@ describe("<BottomNav> iOS-parity layout", () => {
     mockUserRef.value = { id: "u1", modules: {} };
   });
 
+  it("drops the Insights primary slot when the insights module is off (v1.18.0)", () => {
+    // The Insights slot is a fixed primary anchor, but it is now
+    // module-gated: a disabled insights module must remove it from the
+    // strip (and it is excluded from the More hub by the primary-slot
+    // filter, so the module is hidden everywhere, not relocated).
+    mockUserRef.value = { id: "u1", modules: { insights: false } };
+    const html = render();
+    expect(html).not.toContain('href="/insights"');
+    // Sibling primary slots are unaffected.
+    expect(html).toContain('href="/"');
+    expect(html).toContain('href="/medications"');
+    mockUserRef.value = { id: "u1", modules: {} };
+  });
+
+  it("keeps the Insights primary slot when the insights module is on", () => {
+    mockUserRef.value = { id: "u1", modules: { insights: true } };
+    const html = render();
+    expect(html).toContain('href="/insights"');
+    mockUserRef.value = { id: "u1", modules: {} };
+  });
+
   it("gating on a disabled module never throws (v1.18.0)", () => {
     mockUserRef.value = {
       id: "u1",

src/components/layout/__tests__/nav-model.test.ts

@@ -115,17 +115,21 @@ describe("visibleNavDestinations module gate", () => {
     expect(on.indexOf("/cycle")).toBeLessThan(on.indexOf("/insights"));
   });
 
-  it("drops a module-gated entry (mood / labs / coach / achievements) when its module is disabled", () => {
+  it("drops a module-gated entry (mood / labs / coach / achievements / insights) when its module is disabled", () => {
     const disabled = visibleNavDestinations({
       mood: false,
       labs: false,
       coach: false,
       achievements: false,
+      // v1.18.0 — Insights is now `requiresModule: "insights"`, so the
+      // top-level /insights entry drops when the module is off.
+      insights: false,
     }).map((d) => d.href);
     expect(disabled).not.toContain("/mood");
     expect(disabled).not.toContain("/labs");
     expect(disabled).not.toContain("/coach");
     expect(disabled).not.toContain("/achievements");
+    expect(disabled).not.toContain("/insights");
   });
 
   it("keeps every module-gated entry when its module is enabled", () => {
@@ -134,11 +138,13 @@ describe("visibleNavDestinations module gate", () => {
       labs: true,
       coach: true,
       achievements: true,
+      insights: true,
     }).map((d) => d.href);
     expect(enabled).toContain("/mood");
     expect(enabled).toContain("/labs");
     expect(enabled).toContain("/coach");
     expect(enabled).toContain("/achievements");
+    expect(enabled).toContain("/insights");
   });
 
   it("fails open: a missing key or an undefined map keeps the gated entry", () => {

src/components/layout/bottom-nav.tsx

@@ -16,6 +16,7 @@ import {
   isNavDestinationActive,
   mobileMoreHubDestinations,
 } from "@/components/layout/nav-model";
+import type { ModuleKey } from "@/lib/modules/registry";
 import { useMemo, useState } from "react";
 import { useAppSettings } from "@/components/app-settings-provider";
 import { useAuth } from "@/hooks/use-auth";
@@ -57,8 +58,21 @@ const PRIMARY_LEFT: ReadonlyArray<NavLink> = [
   { href: "/medications", tKey: "nav.medications", icon: Pill },
 ];
 
-const PRIMARY_RIGHT: ReadonlyArray<NavLink> = [
-  { href: "/insights", tKey: "nav.insights", icon: Lightbulb },
+// v1.18.0 — the Insights primary slot is module-gated. Insights is now a
+// toggleable module (`requiresModule: "insights"` in the shared nav model),
+// so the fixed slot must respect the same per-user map the More hub already
+// honours rather than pinning a destination the account turned off. When
+// insights is disabled the slot is dropped (it is excluded from the More hub
+// by `BOTTOM_NAV_PRIMARY_SLOT_HREFS`, so a disabled module is hidden
+// everywhere, not relocated). Fail-open: a missing key / unloaded map keeps
+// the slot, mirroring the gate's default-on contract.
+const PRIMARY_RIGHT: ReadonlyArray<NavLink & { requiresModule?: ModuleKey }> = [
+  {
+    href: "/insights",
+    tKey: "nav.insights",
+    icon: Lightbulb,
+    requiresModule: "insights",
+  },
 ];
 
 export function BottomNav() {
@@ -86,6 +100,18 @@ export function BottomNav() {
     [user?.modules, bugReportEnabled],
   );
 
+  // v1.18.0 — drop a module-gated primary slot (Insights) when the account
+  // has that module disabled. Fail-open: a missing key / unloaded map keeps
+  // the slot, mirroring the gate + More-hub default-on contract.
+  const primaryRight = useMemo(
+    () =>
+      PRIMARY_RIGHT.filter(
+        (item) =>
+          !item.requiresModule || user?.modules?.[item.requiresModule] !== false,
+      ),
+    [user?.modules],
+  );
+
   function isActiveLink(href: string) {
     return isNavDestinationActive(href, pathname);
   }
@@ -160,7 +186,7 @@ export function BottomNav() {
             </button>
           </div>
 
-          {PRIMARY_RIGHT.map(renderPrimary)}
+          {primaryRight.map(renderPrimary)}
 
           <button
             type="button"

src/components/layout/nav-model.ts

@@ -118,6 +118,7 @@ export const NAV_DESTINATIONS: ReadonlyArray<NavDestination> = [
     tKey: "nav.insights",
     icon: Lightbulb,
     tourId: "nav-insights",
+    requiresModule: "insights",
   },
   // v1.17.1 (F-3) — the Coach finally gets a single labeled nav home. It
   // was reachable from seven scattered entry points (FAB, hero CTA, empty