* feat(files): public share links for workspace files
* improvement(files): drop reserved public_share columns until used; sync audit mock
* fix(files): share modal tracks authoritative saved state until toggled
* feat(files): per-IP rate limit on public share endpoints
* fix(files): address PR review — public CSV OOM, content cache, share FK, soft-delete filter, download anchor
* fix(files): disable CSV import action in read-only preview (public share)
* refactor(files): drive CSV preview import affordance off readOnly, not disableImport
* fix(files): version public viewer caches by file updatedAt so edits aren't stale
* fix(files): 409 (not corrupt source) when a shared generated doc has no compiled artifact
* feat(files): gate public sharing behind an access-control permission