fix: mobile dialogs and single-chain Frontier rendering

[rayalexvector]

Scope

• Add accessible modal semantics, background isolation, focus containment/restoration, touch-sized closing controls and scrollable short-screen content.
• Keep portrait-only game behavior while allowing an existing dialog to remain usable after rotation.
• Remove the document-wide double-tap handler that swallowed fast taps on different controls; preserve CSS touch constraints.
• Cancel Frontier animation frames on pause/background/state changes and prevent duplicate loops after rapid resume. Preserve visual quality and homepage content.

Verification

• 81 Node tests passed before final browser fixes; focused modal/lifecycle tests and static checks passed afterward.
• Actual mobile modal interaction passed at 320x568, 390x844 and 844x390, including touch scroll, focus and explicit resume.
• Extended browser tests cover real Frontier touch movement, background stop and exactly one update chain.
• Full browser suite runs locally and under the required verify check before merge.

Boundaries

No production data edits, model calls, paid services or homepage redesign. Chromium emulation does not replace physical iOS Safari and VoiceOver acceptance.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-07T20:12:59.649401Z	797ee1a	PR opened

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 797ee1abd2

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[chatgpt-codex-connector]

Avoid inerting an open native save dialog

When a game’s save manager is open and the page is backgrounded and restored, cloud-save.js has an open native dialog.showModal() while the visibility handler in app.js opens the custom pause modal. This assignment makes that native dialog inert, but it remains in the browser top layer above the ordinary .modal-backdrop, leaving touch users unable to interact with either dialog and effectively requiring a reload. Preserve an open top-layer dialog or defer the pause modal until the save dialog closes.

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[rayalexvector]

Follow-up regression found and fixed: a completed no-op cloud pull could emit a progress-replacement event while a newer local play counter update was pending, returning Frontier to its menu. Added a deterministic failing-then-passing transaction regression and retained notification for actual remote replacement. Rapid resume now queues the next frame rather than rendering synchronously for every toggle. Static cache v4 refreshes the shared core for historical SW clients. Current local results: 82 frontend tests and 48 backend integration/runtime tests passed. Full browser checks are rerunning for the final commit.