feat: add EAS build config and app store asset structure (FRE-4572)

- Create eas.json with development, preview, and production build profiles
- Add submit configuration for iOS App Store and Google Play
- Create app store metadata with listing copy, keywords, and requirements
- Add screenshot capture guides for iOS and Android
- Add marketing asset directory structure

packages/mobile/assets/store/README.md

@@ -0,0 +1,67 @@
+# ShieldAI - App Store Metadata
+
+## App Information
+- **App Name:** ShieldAI
+- **Subtitle:** Your Digital Identity Shield
+- **Description:** ShieldAI protects your digital identity in real-time. Monitor data breaches, block spam calls and texts, and verify voices with AI-powered protection. Get instant alerts when your personal information appears online, manage your watch list for new threats, and keep your family safe with VoicePrint verification.
+- **Keyword:** privacy,security,spam,identity,breach,protection,voice,ai
+- **Support URL:** https://shieldai.frenocorp.com/support
+- **Privacy URL:** https://shieldai.frenocorp.com/privacy
+- **Marketing URL:** https://shieldai.frenocorp.com
+
+## iOS App Store Requirements
+
+### Screenshots (Required)
+- iPhone 6.7" (1290x2796): 3-5 screenshots
+- iPhone 6.1" (1170x2532): 3-5 screenshots
+- iPad 10.9" (2048x2732): 3-5 screenshots (if tablet supported)
+- Format: PNG, no rounded corners, no device frame overlays
+
+### App Icon
+- 1024x1024 PNG, no transparency, no rounded corners
+- Place at: `assets/store/ios/app-icon-1024.png`
+
+### Preview Video (Optional)
+- 9:16 or 16:9, 20-90 seconds
+- MP4 format, under 100MB
+
+## Google Play Store Requirements
+
+### Screenshots (Required)
+- Phone (1080x1920 recommended): 2-8 screenshots
+- Tablet (1600x2560 recommended): 2-8 screenshots (if tablet supported)
+- Format: PNG or JPEG, under 8MB each
+
+### App Icon
+- 512x512 PNG, 32-bit with transparency, 1MB or less
+- Place at: `assets/store/android/app-icon-512.png`
+
+### Feature Graphic
+- 1024x500 PNG, 1MB or less, no transparency
+- Place at: `assets/store/android/feature-graphic.png`
+
+### Video (Optional)
+- YouTube URL or uploaded video
+
+## Tier-Based Feature Highlights for Screenshots
+
+### Free Tier Screenshots
+1. Dashboard - Basic exposure summary
+2. SpamShield - Call/text spam detection
+3. Settings - Account and notifications
+
+### Plus Tier Screenshots
+1. DarkWatch - Watch list and exposure feed
+2. Alert notification preview
+3. Real-time breach monitoring
+
+### Premium Tier Screenshots
+1. VoicePrint - Family enrollment
+2. Voice analysis results
+3. Deepfake detection status
+
+## Screenshot Notes
+- Screenshots should show the app in both light and dark mode
+- Highlight key differentiators: real-time alerts, AI voice verification, family protection
+- Use consistent device mockups across stores
+- Localization-ready: avoid hardcoded text in screenshot UI