fix: address canvas getting 0x0 on React strict mode

[zplata]

Under React 19's Strict Mode, our previous change to actually set width/height 0x0 to the canvas on canvas unmount had a side effect. In strict mode, setCanvasRef gets an extra detach/reattach during mount, and that fake detach gets the 0x0 treatment. So when the element actually mounts, it's possible the canvas has 0x0. This fixes that behavior so we compare the prev/incoming canvas and if they're the same, we ignore the zero-out — if they differ, the old canvas really is gone and still gets released. The queueMicrotask defers the comparison to when a reattach should happen.

Also bumps the JS runtime to 2.42.1.

Addresses this comment from #440: #440 (comment)

[Copilot]

🟢 Approval recommended

The ref lifecycle fix is correctly scoped, preserves real cleanup, and has focused regression coverage.

Pull request overview

Prevents React 19 Strict Mode’s temporary ref detachment from clearing a live canvas while preserving backing-store cleanup on actual unmount.

Changes:

• Defers canvas cleanup and verifies the detached canvas was not reattached.
• Adds regression coverage for unmounting and immediate reattachment.
• Upgrades Rive runtimes to 2.42.1.

File summaries

File	Description
src/hooks/useRive.tsx	Makes canvas cleanup Strict Mode-safe.
test/useRive.test.tsx	Tests deferred cleanup and reattachment.
package.json	Upgrades runtime dependencies.
package-lock.json	Locks upgraded runtime packages.

Review details

• Files reviewed: 3/4 changed files
• Comments generated: 0
• Review effort level: Balanced

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[bodymovin]

LGTM