Part of WOOMOB-935

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Description

This PR moves shared image assets used by both the main app and POS to the WooFoundation module, consolidating them in preparation for POS modularization (#16176).

Key Changes:

• Created SharedImageAsset enum in WooFoundation with standardized SwiftUI Image and UIImage access
• Moved 5 shared image assets from main app to WooFoundation:
  • card-reader-update-progress-arrow and card-reader-update-progress-checkmark (used in reader update progress)
  • coupons (used in empty states)
  • location (used in reader connection alerts)
  • shopping-bags (used in cart empty state)
• Updated main app to use SharedImageAsset instead of direct image names
• Replaced POS-specific UIImage+POS.swift extension with SharedImageAsset usage
• Updated POS views to use SharedImageAsset for consistent image access

Benefits:

• Eliminates image duplication between app and POS module
• Provides type-safe image access through enum cases
• Centralizes shared resources in WooFoundation for easier maintenance
• Reduces coupling between POS and main app resources

Steps to reproduce

A quick regression test in POS would be helpful:

1. Build and run the app on an iPad
2. Navigate to POS
3. Verify the following images display correctly:
   • Empty cart shows shopping bags icon
   • Empty coupons list shows coupons icon
   • Card reader connection location alerts show location icon
   • Card reader update progress shows arrow/checkmark icons

Testing information

I tested the following scenarios on iPad A16 iOS 26.0 simulator, and SwiftUI previews in Xcode 26.

column 1	column 2

Card reader software update:

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.