[Android] Scope preload state to per-cache entry

[markmur]

Promotes preload lifecycle state from cache-global to per-cache-entry, so each CheckoutPreload handle reflects only the checkout it preloaded rather than a shared singleton state. The Entry now owns its state and weak observer; the cache keeps a keyed handles registry and transitions are view-guarded, so a navigation/error/eviction callback only mutates the entry that fired it. The cache stays single-slot today, but this removes the last cache-global coupling and is forward-compatible with a future multi-entry keyed cache.

This is the Android port of #454 (Swift). Android has no keep-alive or scheduled-expiry timers, so this is a strict subset — only state + observer move onto the entry; expiry stays lazy in take().

Public API is unchanged (apiCheck clean). See distinct keys observe independently in PreloadObservabilityTest for the behavior that regressed under the old shared-state model.

[markmur]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• [Android] Scope preload state to per-cache entry #455 👈 (View in Graphite)
• [Android] Add preload state observability #451 : 1 other dependent PR (#447 )
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

React Native — Coverage Report

Lines	Statements	Branches	Functions
	91.85% (327/356)	87.98% (183/208)	100% (86/86)

[github-actions]

Package Size

Platform	Artifact	Base	Head	Delta
Android	release AAR	250.1 KiB	250.9 KiB	+784 B

Android file breakdown

File	Base	Head	Delta
classes.jar	265.5 KiB	266.5 KiB	+1022 B
res/layout/checkout_view_content.xml	2.2 KiB	2.2 KiB	0 B
res/layout/checkout_sheet_content.xml	2.0 KiB	2.0 KiB	0 B
res/values/values.xml	1.2 KiB	1.2 KiB	0 B
R.txt	1.1 KiB	1.1 KiB	0 B
proguard.txt	798 B	798 B	0 B
AndroidManifest.xml	578 B	578 B	0 B
res/drawable/close.xml	431 B	431 B	0 B
res/menu/checkout_menu.xml	354 B	354 B	0 B
META-INF/com/android/build/gradle/aar-metadata.properties	157 B	157 B	0 B

Measured from the PR base SHA and PR head SHA. The file breakdown shows uncompressed sizes within each package artifact, so individual files do not sum to the compressed artifact total. This comment reports package artifact sizes only; it is not a final app binary-size report.

[bitrise]

Install this build

Open Tophat, select your target device, then click Install. Links open on the Mac running Tophat.

SDK	Install
React Native	Install with Tophat
Swift	Install with Tophat
Kotlin	Install with Tophat

Checkout Kit E2E results

Status	Suite	Target	Platform	OS version tag	Device
✅	tests/shared/launch-smoke.yaml	kotlin	android	latest	Google Pixel 9 Android 17.0

[markmur]

Closing - deferring until we actually need multi-slot