fix(web): companion-gate the store banner + manual intro trigger (#61 residual)

Only the auto-popup was companion-gated — inside the companion WebView
users still saw the 'install the companion' banner in the App Store and
could pop the intro overlay through it. Gates all three paths on
isCompanionApp(): CompanionBanner self-hides, openCompanionIntro() is a
no-op, and the manual-open watcher in CompanionIntroOverlay refuses to
open (the overlay's raw window check also moves to the canonical helper
so there is exactly one detection). No APK change.

neode-ui/src/composables/__tests__/useCompanionIntro.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect, afterEach, beforeEach } from 'vitest'
+import { companionIntroRequested, openCompanionIntro } from '../useCompanionIntro'
+
+// #61: the manual intro trigger (App Store banner etc.) must be a no-op inside
+// the companion app's WebView — the "install the companion" pitch is nonsense
+// where the user is already running it. The auto-popup was already gated
+// (CompanionIntroOverlay.onMounted); openCompanionIntro is the second, manual
+// path and the banner render (CompanionBanner) the third.
+
+type TestWindow = Window & { ArchipelagoNative?: unknown }
+const w = window as TestWindow
+
+beforeEach(() => {
+  companionIntroRequested.value = false
+})
+
+afterEach(() => {
+  delete w.ArchipelagoNative
+})
+
+describe('openCompanionIntro', () => {
+  it('raises the manual intro request in a plain browser/PWA', () => {
+    expect(companionIntroRequested.value).toBe(false)
+    openCompanionIntro()
+    expect(companionIntroRequested.value).toBe(true)
+  })
+
+  it('is a no-op inside the companion app (bridge with openInApp)', () => {
+    w.ArchipelagoNative = { openInApp: () => {}, openExternal: () => {} }
+    openCompanionIntro()
+    expect(companionIntroRequested.value).toBe(false)
+  })
+
+  it('still fires when the bridge exists but is not the companion shell', () => {
+    // Partial bridge (no openInApp) is not the companion app — a future
+    // embedder must still see the pitch.
+    w.ArchipelagoNative = { openExternal: () => {} }
+    openCompanionIntro()
+    expect(companionIntroRequested.value).toBe(true)
+  })
+})