[UI] Preserve SwiftUI sizing and replacement transitions

[NachoSoto]

Summary

• add explicit SwiftUI image sizing modes while preserving aspect-fit as the default
• give each rendered image a stable SwiftUI identity so placeholder-to-source replacements run their existing opacity transition
• cover the new sizing initializers in the retained-state test matrix

Motivation

WatchChess tournament cells need the legacy scaleToFill presentation without falling back to a UIViewRepresentable. The existing SwiftUI implementation also attached a transition without changing view identity, so replacing a placeholder with the final image did not actually insert a transitioning view.

Validation

• Swift 6 iOS Simulator library build
• iOS Simulator package test action
• strict SwiftLint: 0 violations across 34 files

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-03T18:57:14.580174Z	6e01b2e	Draft marked ready

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[chatgpt-codex-connector]

💡 Codex Review

https://github.com/NachoSoto/AsyncImageView/blob/6e01b2ec20c14b6488d2d006037bb69b154432f1/AsyncSwiftUIImageView.swift#L152
Add an actual stretch-to-fill mode

When .fill is selected for a non-square image in a differently shaped frame, aspectRatio(nil, contentMode: .fill) preserves the image's aspect ratio; it is SwiftUI's aspect-fill behavior and cannot reproduce stretch-to-bounds/UIImageView.ContentMode.scaleToFill. The image will instead extend beyond one frame dimension and either bleed or be cropped, so the legacy scale-to-fill use case described by this change still needs a distinct mode that omits the aspect-ratio modifier.

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https://github.com/NachoSoto/AsyncImageView/blob/6e01b2ec20c14b6488d2d006037bb69b154432f1/AsyncSwiftUIImageView.swift#L153-L154
Base replacement animation on the incoming result

When a non-cache-hit image is currently displayed and the next result is a cache hit, changing the ID removes the old subtree using that old subtree's .easeOut transition; the incoming view's animation(nil) does not cancel the outgoing transition. The replacement can therefore still cross-fade or linger despite cache hits being intended to swap immediately, unlike AsyncImageView.updateImage; drive the whole replacement transaction from the incoming result or otherwise disable the outgoing animation for cached replacements.

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