fix(captures): hide macOS-only copy when running on Windows / Linux

Two surfaces leaked macOS-specific copy onto other platforms:

1. The Input Monitoring + Accessibility rows in the readiness
   checklist rendered everywhere. On Windows/Linux the Rust permission
   stubs return true, so the rows showed as permanent green checkmarks
   with copy like "macOS allows Voicebox to detect your global
   shortcut." — nonsense when you're on Windows. Gate both rows on a
   userAgent-based isMacOS check so they only render where the
   underlying TCC permission actually exists.

2. The global-shortcut setting description ended with "macOS will ask
   for Input Monitoring permission the first time you turn this on."
   That sentence rendered on every platform. The readiness checklist
   already surfaces the TCC requirement at the right moment on macOS,
   so the description doesn't need the platform note — drop it from
   en / ja / zh-CN / zh-TW.

Other macOS strings (AccessibilityNotice, InputMonitoringNotice, their
"stillMissing" hints) are already gated behind the Rust permission
booleans returning false, which never happens on Windows/Linux, so they
stay inert without further changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

app/src/components/CapturesTab/DictationReadinessChecklist.tsx

@@ -232,39 +232,50 @@ export function DictationReadinessChecklist({
         />
       )}
 
-      <ChecklistRow
-        icon={<Keyboard className="h-3.5 w-3.5" />}
-        title={t('captures.readiness.inputMonitoring.label')}
-        description={
-          readiness.inputMonitoring
-            ? t('captures.readiness.inputMonitoring.ready')
-            : t('captures.readiness.inputMonitoring.missing')
-        }
-        ready={readiness.inputMonitoring}
-        action={
-          <Button size="sm" onClick={readiness.openInputMonitoringSettings} className="gap-1.5">
-            <ExternalLink className="h-3.5 w-3.5" />
-            {t('captures.readiness.inputMonitoring.openSettings')}
-          </Button>
-        }
-      />
+      {/* Input Monitoring + Accessibility are macOS-only TCC permissions.
+          The Rust stubs return true on Windows/Linux, so rendering these
+          rows there would show permanent green checkmarks with copy
+          that talks about macOS — noise. Hide on non-mac. */}
+      {isMacOS && (
+        <ChecklistRow
+          icon={<Keyboard className="h-3.5 w-3.5" />}
+          title={t('captures.readiness.inputMonitoring.label')}
+          description={
+            readiness.inputMonitoring
+              ? t('captures.readiness.inputMonitoring.ready')
+              : t('captures.readiness.inputMonitoring.missing')
+          }
+          ready={readiness.inputMonitoring}
+          action={
+            <Button size="sm" onClick={readiness.openInputMonitoringSettings} className="gap-1.5">
+              <ExternalLink className="h-3.5 w-3.5" />
+              {t('captures.readiness.inputMonitoring.openSettings')}
+            </Button>
+          }
+        />
+      )}
 
-      <ChecklistRow
-        icon={<Accessibility className="h-3.5 w-3.5" />}
-        title={t('captures.readiness.accessibility.label')}
-        description={
-          readiness.accessibility
-            ? t('captures.readiness.accessibility.ready')
-            : t('captures.readiness.accessibility.missing')
-        }
-        ready={readiness.accessibility}
-        action={
-          <Button size="sm" onClick={readiness.openAccessibilitySettings} className="gap-1.5">
-            <ExternalLink className="h-3.5 w-3.5" />
-            {t('captures.readiness.accessibility.openSettings')}
-          </Button>
-        }
-      />
+      {isMacOS && (
+        <ChecklistRow
+          icon={<Accessibility className="h-3.5 w-3.5" />}
+          title={t('captures.readiness.accessibility.label')}
+          description={
+            readiness.accessibility
+              ? t('captures.readiness.accessibility.ready')
+              : t('captures.readiness.accessibility.missing')
+          }
+          ready={readiness.accessibility}
+          action={
+            <Button size="sm" onClick={readiness.openAccessibilitySettings} className="gap-1.5">
+              <ExternalLink className="h-3.5 w-3.5" />
+              {t('captures.readiness.accessibility.openSettings')}
+            </Button>
+          }
+        />
+      )}
     </div>
   );
 }
+
+const isMacOS =
+  typeof navigator !== 'undefined' && /Mac|iPhone|iPad/.test(navigator.userAgent);