fix(core): repaint when device pixel ratio changes

[chh-ay]

Problem

A display-density change can leave the host at the same CSS size, so ResizeObserver does not fire and the canvas keeps its old backing scale until another interaction.

Change

• arm a resolution matchMedia listener at the current DPR
• re-arm it after each change, refresh the scroll-size limit, invalidate pixels, and schedule one render
• detach the listener on destroy
• cover 1→2→1 changes, repeated teardown, main-thread canvas sizing, and Worker viewport DPR messages
• exercise the same transition in Chromium and Firefox; the @portability test also runs in WebKit in Required CI
• add the required @sheetwrite/core patch changeset

Verification

• bun test packages/core/test/device-pixel-ratio.test.ts — 2 pass
• bun test packages/core/test — 762 pass
• focused Chromium + Firefox DPR browser test — 2 pass
• bun run typecheck — pass
• bun run lint — pass (one existing oversized generated-data warning)
• GITHUB_BASE_REF=0.4.0 bun run changeset:ci — pass

The broader local browser run passed 173 tests; the unrelated sustained-scroll timing check reported 40 ms against its 35 ms target on both attempts. The full root unit run retained the seven known baseline failures from issue #33 (one stale docs inventory assertion and six stale recorded benchmark toolchain assertions). Required CI is the merge gate.

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Project	Deployment	Actions	Updated (UTC)
sheetwrite	Ready	Preview, Comment	Jul 27, 2026 5:58am