fix(client): use browser :hover for card-preview dismiss checks

[matthewevans]

Battlefield card previews never appeared over remote desktop (RDP) and flickered locally with a non-zero hover delay. Both timer-based dismiss checks — the 300ms poll (usePreviewDismiss) and the 50ms delayed-clear (uiStore.inspectObject) — tested "is the cursor still over a card?" by sampling document.elementFromPoint() against a JS-tracked pointer that only updates on pointermove. Over sparse/coalesced RDP pointer streams that coordinate goes stale a few px off the card while the OS cursor is genuinely on it, so the check false-negatived and dismissed (or cancelled the pending show for) a live preview.

Battlefield cards were uniquely affected: their hover element carries a Framer-Motion layoutId that emits spurious mouseleave events routed through the delayed-clear; hand cards have no layoutId and never triggered the stale-pointer check.

Switch both timer-based checks to the browser's authoritative [data-card-hover]:hover element — the engine's continuous hit-test, correct with zero pointermove events — and remove the now-dead lastPointer tracking. The pointerdown-outside handler keeps elementFromPoint (it reads fresh event coordinates).

Summary by CodeRabbit

• Bug Fixes
  • Improved hover detection for previews and cards by relying on the browser’s active hover state.
  • Prevented previews from dismissing unexpectedly during layout changes or motion transitions.
  • Removed issues caused by stale pointer-position tracking, while preserving dismissal when clicking outside the preview.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 7eb3f970-5eac-4bfd-af47-83dc0efc7b3e

📥 Commits

Reviewing files that changed from the base of the PR and between 192897c and 1f253e4.

📒 Files selected for processing (3)

• client/src/hooks/usePreviewDismiss.ts
• client/src/stores/__tests__/uiStoreHoverLatency.test.ts
• client/src/stores/uiStore.ts

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📝 Walkthrough

Walkthrough

Preview hover retention and dismissal now rely on the browser’s continuous [data-card-hover]:hover state rather than pointer coordinates tracked through JavaScript. Store tests were updated to mock document.querySelector for the new behavior.

Changes

Hover-state preview handling

Layer / File(s)	Summary
CSS hover detection and dismissal flow client/src/stores/uiStore.ts, client/src/hooks/usePreviewDismiss.ts, client/src/stores/__tests__/uiStoreHoverLatency.test.ts	Removed pointer-position tracking and coordinate hit-testing, added [data-card-hover]:hover checks for preview retention and dismissal, and updated hover-latency tests to mock the new query path.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• phase-rs/phase#6239: Updates the same hover-preview logic to use [data-card-hover]:hover instead of pointer-coordinate hit-testing.

Suggested reviewers: parthmishra

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: switching card-preview dismiss checks to browser :hover state.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ship/card-preview-hover-dismiss

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