fix: Change NFC tag writing

[philprime]

Summary

• Extracted LinkDetailNFCSharingViewModel, NFCDeviceDelegate, NFCSharingState; container view is view-only with .sentryTrace("LINK_DETAIL_NFC_SHARING").
• Fixed CoreNFC write flow: retain delegate; handle multi-tag via restartPolling(); check NDEF status/capacity; set alertMessage and invalidate() on success/error.
• Preserved error handling pattern and Sentry breadcrumbs/events.
• Entitlements (com.apple.developer.nfc.readersession.formats) and NFCReaderUsageDescription verified.

Why

• Previous implementation could drop callbacks due to deallocated delegate and didn't follow Apple guidance, causing writes to fail.

References

• Apple docs: https://developer.apple.com/documentation/corenfc/building-an-nfc-tag-reader-app

Testing

• Requires physical device with NFC (not simulator).
• Present only one tag at a time; ensure tag supports NDEF and has sufficient capacity.
• iOS 13+ required for CoreNFC NDEF writing.

[Copilot]

Pull Request Overview

This PR refactors the NFC sharing functionality to follow MVVM architecture pattern and fixes the CoreNFC write flow by implementing proper tag handling and error management.

Key changes:

• Extracts business logic from the container view into a dedicated ViewModel pattern
• Implements proper CoreNFC delegate with tag capacity checks and multi-tag handling
• Adds comprehensive error handling with specific NFC error cases and Sentry integration

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
NFCSharingState.swift	Defines state enum for NFC sharing operations (ready, scanning, success, error)
NFCDeviceDelegate.swift	New CoreNFC delegate handling tag detection, connection, and NDEF writing with proper error cases
LinkDetailNFCSharingViewModel.swift	ViewModel managing NFC session lifecycle, delegate coordination, and analytics tracking
LinkDetailNFCSharingContainerView.swift	Refactored container view using MVVM pattern, removing inline NFC logic
App.entitlements	Adds NDEF format to NFC reader session entitlements

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