fix(core): preserve cached worker view buffers

[chh-ay]

Summary

• transfer only renderer-owned copies of packed and generic view buffers
• preserve cached frozen-pane views across repeated worker paints
• cover real structured-clone transfer semantics and sub-row browser repaints

Pre-fix reproduction

bun test packages/core/test/worker-renderer.test.ts produced 7 pass / 1 fail. The second paint threw DataCloneError: The object can not be cloned when the faithful fake Worker attempted to transfer the already-detached cached view buffers.

Verification

• bun test packages/core/test/worker-renderer.test.ts — 10 pass
• bun test packages/core/test — 756 pass
• bun run typecheck — pass
• bun run api:check — pass
• bun run lint — pass (existing corpus-size warning only)
• bun scripts/check-import-cycles.ts — pass
• bun run changeset:ci — pass
• focused Chromium cached-view browser regression — pass
• focused Firefox cached-view browser regression — pass
• Chromium suite — 157 pass / 1 pre-existing long-task-budget failure; the same test fails at base commit 0e09ecc
• root bun test — 1270 pass / the same 7 known unrelated failures (compatibility inventory + six billion-cell gate checks)

Local WebKit could not launch because host dependencies require interactive sudo; Required CI supplies those dependencies and remains the browser gate.

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Project	Deployment	Actions	Updated (UTC)
sheetwrite	Ready	Preview, Comment	Jul 26, 2026 5:24pm