A bare SQLITE_CORRUPT/NOTADB on a live write (not FTS-scoped, not a
replaced file) now sets a sticky per-instance flag: later writes fail
fast with StateDbCorruptError, the handle never reopens after close(),
and close() skips its explicit PASSIVE WAL checkpoint. Gateway and agent
flush paths divert pending transcripts to JSONL/spool like the replaced
case instead of retrying forever.
Field evidence: a handle that kept writing for ~50 minutes after the
first structural error checkpointed 15 pages under the wrong page
numbers on shutdown (page 1 <- messages_fts_trigram_data leaf), turning
"malformed" into "file is not a database".
Refs #90837, #90950, #97940, #89332, #45383
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CNX8rNYHqA5pT4tAGSzXtb
bcc2e65818