The TTY got the fast cold start in #1109; every JSON surface still waited
for the full parse because a payload has no way to say "partial". Add one.
- `hydration: { complete, indexedFiles, totalFiles }` on the menubar payload,
add-only and emitted ONLY by the resident serve child (which polls, and
therefore converges). Absence keeps meaning "complete", so every one-shot
output is byte-identical and no script can be handed partial data.
- serve: a cold child answers `status --format menubar-json` from the files
the requested period can show (same mtime floor as the TUI) and schedules
the unfloored fill behind it. Partial answers are never memoized; requests
waiting behind the fill are heartbeated by id so the client's no-output
watchdog stays armed.
- `stale` keeps its own meaning: a first paint is fresh but partial, so it
reports through `hydration` and never sets `stale`.
- desktop app and web dash render an honest "indexing history · N/M files"
notice while `complete` is false.
iamtoruk
be1b212a3f