fix(quick-260610-jlp-01): wire SettingsSheet 'How to enable' to open InstructionSheet

- Add instructionsOpen state to SettingsSheet
- Change broken onClick={onClose} to onClick={() => setInstructionsOpen(true)}
- Render InstructionSheet conditionally when instructionsOpen=true
- Add InstructionSheet.test.tsx: asserts dialog opens + onClose not called (UAT-05-T4)

apps/pwa/src/components/SettingsSheet.tsx

@@ -24,6 +24,7 @@
 import { useEffect, useRef, useState } from 'react'
 import { X, Bell, AlertCircle, Loader2 } from 'lucide-react'
 import { usePushSubscription } from '../hooks/usePushSubscription.js'
+import { InstructionSheet } from './InstructionSheet.js'
 
 // CR-04: fetch VAPID key (from sessionStorage cache if available) for the
 // tap-gated subscribe() path.  Same logic as PushPermissionPrompt.
@@ -51,6 +52,7 @@ interface SettingsSheetProps {
 export function SettingsSheet({ isOpen, onClose }: SettingsSheetProps) {
   const { subscribe, permission, isSubscribed, setEnabled } = usePushSubscription()
   const [isTogglingOn, setIsTogglingOn] = useState(false)
+  const [instructionsOpen, setInstructionsOpen] = useState(false)
   // CR-04: pre-fetch the VAPID key into state so the toggle tap handler can call
   // subscribe(registration, vapidKey) without any network await before pushManager.subscribe().
   const [vapidKey, setVapidKey] = useState<string | null>(null)
@@ -370,7 +372,7 @@ export function SettingsSheet({ isOpen, onClose }: SettingsSheetProps) {
                 Notifications are blocked in your browser settings.{' '}
               </span>
               <button
-                onClick={onClose}
+                onClick={() => setInstructionsOpen(true)}
                 style={{
                   background: 'none',
                   border: 'none',
@@ -388,6 +390,10 @@ export function SettingsSheet({ isOpen, onClose }: SettingsSheetProps) {
           </div>
         )}
       </div>
+
+      {instructionsOpen && (
+        <InstructionSheet onClose={() => setInstructionsOpen(false)} />
+      )}
     </>
   )
 }