* fix(core): platformWriteSync must retry transient rename locks, not truncate readers (#1540)
platformWriteSync fell back to a non-atomic fs.writeFileSync(filePath) on ANY
error from the temp+rename path. On Windows, renameSync onto a target a reader
holds open throws EPERM/EBUSY/EACCES (the common case for hot files like
STATE.md), so the fallback fired and a concurrent reader saw the file
mid-truncation.
Mirror the capability-ledger rename-retry idiom: retry transient lock errnos
(EPERM/EBUSY/EACCES) with a bounded Atomics.wait backoff; on a persistent lock,
surface the error rather than do the truncating non-atomic write. Genuinely
unrenameable cases (EXDEV cross-device) and tmp-write failures still fall back.
Claude-Session: https://claude.ai/code/session_01R88n7Q54bAaVHFkDbbH1yz
* chore(changeset): Fixed fragment for #1541 (platformWriteSync rename retry)
Claude-Session: https://claude.ai/code/session_01R88n7Q54bAaVHFkDbbH1yz
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Co-authored-by: Tom Boucher <trekkie@nomorestars.com>
