Part checks counted bytes from the network stream while the joined archive
was hashed from disk, so a truncated write passed part verification and only
failed later as "런타임 아카이브 해시 불일치". Verify size and hash from the
written file, check the joined size before its hash, and retry a failed part
up to 3 times.
Auto-update could not work at all: the installer was 189 MB because it carried
the local speech engine and ffmpeg, and the download feed rejects uploads over
about 100 MiB, so update metadata could never be published.
The installer now leaves those components out and the app fetches them the first
time they are needed, verifying every part and the joined archive before
installing. The installer is 90.6 MiB, the update feed is published again, and
updates stay small because the engine is not re-sent on every release.
The fetch is visible and recoverable: the download runs with progress, a failed
install cleans up after itself, and Settings > STT shows the runtime status with
a manual download action for when the automatic one cannot run.
