fileCacheValidator: hasYdoc && !isLive rows now validate as
y<YDOC_CONVERT_EPOCH>:<ydocTag> (revision-0 collab-only rows included); live
rows and untagged older backends stay uncacheable. The remote source caches
the CONVERTED KiCad text — a warm load skips the download and the measured
~2s-class ydoc→s-expr conversion — and the unconvertible-ydoc plain fallback
is cached under the same tag, ending the stale-ydoc double-fetch. A ydoc
response under a revision-form validator (room appeared mid-listing) stays
uncached, preserving the old race guard exactly.
Measured (Arduino Leonardo, dev stack): cold 52 file GETs → warm reload 0.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VLSht9cadprtT2mhynawWu
3e53ac37f4