feat(shortcuts): use game artwork for pinned icons

[papi-ux]

Summary

• resolve the selected Polaris game's trusted square icon artwork through the existing memory, disk, and bounded fetch path
• pass that bitmap through the adaptive shortcut icon hook
• keep ic_pc_scut as the fail-closed fallback when trusted game artwork is unavailable
• cancel duplicate/lifecycle-ended artwork requests and synchronize memory-cache access now shared by UI and IO threads

This changes the icon used when a player pins a game. It does not discover missing artwork or change Artwork Studio matching; those remain host/catalog responsibilities.

Refreshed integration verification

Exact head: f6e580d04bba0f03d2d2b3a69483ef5acc7e3bf3

The feature branch was merged forward, without rewriting history, onto protected Nova master at e8b3d3fcae35af58c1366a74048933095c17b231.

• diff check passed
• focused shortcut artwork, cancellation, Activity wiring, and adaptive bitmap tests passed
• full current-master JVM suite: 1,495 tests passed
• current-master root debug lint passed
• merge simulation with Doctor PR Doctor: stream raw evidence and execute refreshed safe actions #262 is conflict-free
• exact-head GitHub public hygiene, CodeQL, lint/JVM/helper tests, and release APK assembly passed
• the PR workflow intentionally skipped emulator smoke

Device evidence and remaining gate

Earlier feature-only evidence proved that Launcher3 accepted and pinned Phasmophobia with a persisted bitmap, exact ShortcutTrampoline, host/game/HDR extras, and a visible home tile; no game or stream was launched, and the test device was restored.

That evidence predates the refreshed integration head and is retained as supporting evidence only. A short exact-head pin/remove smoke is still required before this draft is ready.

Boundaries

No poster cropping, artwork discovery, second downloader, shortcut lifecycle expansion, release, tag, or device activation is included.

[papi-ux]

Staged in the Nova 1.4.0 integration PR #267 with its original commits preserved. The Game Detail conflict was resolved by retaining both artwork-backed shortcut icons and the newer state-aware pin confirmation flow. This PR will remain open until the integration PR passes and merges.