docs: add App Store screenshot capture HOWTO

Step-by-step procedure for capturing screenshots across macOS, iPhone,
and iPad for App Store submission. Documents correct simulators,
accepted dimensions, and common pitfalls.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vveerrgg

dev/qa/screenshots/HOWTO.md

@@ -0,0 +1,177 @@
+# App Store Screenshot Capture — HOWTO
+
+## Overview
+
+Screenshots for the NostrKey Safari extension across macOS, iPhone, and iPad. All screenshots show the extension running in Safari on the test page at **nostrkey.com/test**.
+
+## Accepted Dimensions
+
+### Mac App Store
+| Size | Method |
+|------|--------|
+| **2560 x 1600** | Safari window at 1280x800 on Retina display |
+| 2880 x 1800 | Safari window at 1440x900 on Retina display |
+| 1280 x 800 | Non-Retina (not recommended) |
+| 1440 x 900 | Non-Retina (not recommended) |
+
+### iPhone (6.7" display)
+| Size | Simulator |
+|------|-----------|
+| **1284 x 2778** | **iPhone 13 Pro Max** |
+| 1242 x 2688 | iPhone 11 Pro Max (6.5") |
+
+### iPad (12.9" / 13" display)
+| Size | Simulator |
+|------|-----------|
+| **2048 x 2732** | **iPad Pro 12.9-inch (6th generation)** |
+| 2064 x 2752 | iPad Pro 13-inch (M4) |
+
+### WRONG Simulators (rejected by App Store Connect)
+- **iPhone 17 Pro Max** → 1320 x 2868 (not accepted)
+- **iPhone 14 Pro Max** → 1290 x 2796 (not accepted)
+
+## Screenshot Set (8 per platform)
+
+| File | Screen | Notes |
+|------|--------|-------|
+| `locked-vault.png` | Extension locked, password prompt | Extension popup open |
+| `unlocked-vault.png` | Profile view with QR code | Shows npub + QR |
+| `vault.png` | Encrypted Vault / API Keys / Nostr Keys | Vault tab |
+| `apps.png` | App permissions | Apps tab, "No permissions granted yet" |
+| `relays.png` | Relay connections list | Relays tab |
+| `settings.png` | Security, Sync, Advanced | Settings tab |
+| `signing-prompt.png` | Permission Request dialog | "nostrkey.com wants to: Sign an event" |
+| `signed-event.png` | Signed event JSON result | Shows OK badge + full JSON |
+
+## Directory Structure
+
+```
+dev/qa/screenshots/
+├── HOWTO.md          ← this file
+├── macos/            ← 2560x1600 (8 screenshots)
+├── iphone/           ← 1284x2778 (8 screenshots)
+└── ipad/             ← 2048x2732 (8 screenshots)
+```
+
+## Prerequisites
+
+- Xcode with iOS simulators installed
+- NostrKey Xcode project at `dev/apple/NostrKey.xcodeproj`
+- Test page deployed to nostrkey.com/test (GitHub Pages)
+- Safari extension enabled on each device/simulator
+
+## Procedure — macOS
+
+### 1. Build and launch the macOS Safari extension
+```bash
+xcodebuild -project dev/apple/NostrKey.xcodeproj \
+  -scheme "NostrKey (macOS)" -configuration Debug build
+
+open ~/Library/Developer/Xcode/DerivedData/NostrKey-*/Build/Products/Debug/NostrKey.app
+```
+
+### 2. Enable in Safari
+- Safari → Settings → Extensions → enable NostrKey
+- Set permissions to allow on nostrkey.com
+
+### 3. Resize Safari window
+```bash
+osascript -e 'tell application "Safari" to set bounds of front window to {0, 0, 1280, 800}'
+```
+Note: `window.resizeTo()` is blocked by Safari. Must use AppleScript.
+
+### 4. Navigate to test page
+```bash
+osascript -e 'tell application "Safari" to set URL of current tab of front window to "https://nostrkey.com/test"'
+```
+
+### 5. Capture each screen
+Open the extension popup, set up the desired view, then:
+```bash
+# Full-screen capture (popup stays open since no interaction needed)
+screencapture dev/qa/screenshots/macos/locked-vault.png
+
+# Crop to Safari window (50px offset = menu bar on Retina)
+sips --cropOffset 50 0 --cropToHeightWidth 1600 2560 dev/qa/screenshots/macos/locked-vault.png
+```
+
+To find exact Safari window position:
+```bash
+osascript -e 'tell application "Safari" to get bounds of front window'
+# Returns: {left, top, right, bottom} — multiply by 2 for Retina pixels
+```
+
+## Procedure — iPhone
+
+### 1. Create the correct simulator (one-time)
+```bash
+# iPhone 13 Pro Max → 1284x2778 (ACCEPTED)
+xcrun simctl create "iPhone 13 Pro Max" \
+  com.apple.CoreSimulator.SimDeviceType.iPhone-13-Pro-Max \
+  com.apple.CoreSimulator.SimRuntime.iOS-26-2
+```
+
+### 2. Boot, build, install
+```bash
+xcrun simctl boot <DEVICE_ID>
+
+xcodebuild -project dev/apple/NostrKey.xcodeproj \
+  -scheme "NostrKey (iOS)" -configuration Debug \
+  -destination "id=<DEVICE_ID>" build
+
+xcrun simctl install <DEVICE_ID> \
+  ~/Library/Developer/Xcode/DerivedData/NostrKey-*/Build/Products/Debug-iphonesimulator/NostrKey.app
+```
+
+### 3. Launch the app manually
+`xcrun simctl launch` often fails on fresh simulators. Tap the NostrKey icon on the home screen instead. This registers the extension with Safari.
+
+### 4. Enable in Safari
+In the simulator's Safari:
+- Tap the extensions icon (puzzle piece) or `AA` button
+- Manage Extensions → enable NostrKey
+- Navigate to nostrkey.com/test
+
+### 5. Capture
+```bash
+xcrun simctl io <DEVICE_ID> screenshot dev/qa/screenshots/iphone/locked-vault.png
+```
+No cropping needed — simulator screenshots are exact device resolution.
+
+## Procedure — iPad
+
+Same as iPhone but with iPad simulator:
+
+### 1. Create simulator (one-time)
+```bash
+# iPad Pro 12.9" (6th gen) → 2048x2732 (ACCEPTED)
+xcrun simctl create "iPad Pro 12.9 6th" \
+  com.apple.CoreSimulator.SimDeviceType.iPad-Pro-12-9-inch-6th-generation-8GB \
+  com.apple.CoreSimulator.SimRuntime.iOS-26-2
+```
+
+### 2-5. Same as iPhone
+Build, install, launch manually, enable extension, capture:
+```bash
+xcrun simctl io <DEVICE_ID> screenshot dev/qa/screenshots/ipad/locked-vault.png
+```
+
+## Current Simulator IDs (created 2026-03-03)
+
+| Simulator | ID |
+|-----------|-----|
+| iPhone 13 Pro Max | `1C222EE7-DC03-486E-8608-5B16310259E5` |
+| iPad Pro 12.9" 6th | `D80D7F11-B50B-4169-81C4-3026C8538765` |
+
+To list all simulators:
+```bash
+xcrun simctl list devices available | grep -i "iphone\|ipad"
+```
+
+## Tips
+
+- **Extension not detected?** Refresh the page. Safari sometimes delays extension injection.
+- **`file://` URLs don't work** — Safari extensions won't inject on local files. Use nostrkey.com/test or a local HTTP server (`python3 -m http.server 8080` from `docs/`).
+- **Signing prompt is time-sensitive** — tap "Sign Test Event" on the test page and capture quickly before the prompt auto-dismisses.
+- **Clean up simulators** when done: `xcrun simctl delete <DEVICE_ID>`
+- **Simulator master password:** `123456789`