Startup only quarantined a 0-byte / all-NUL state.db. A file whose first page
was clobbered with record bytes (#102198) went straight to sqlite3.connect,
which raised "file is not a database" and deleted the -wal sidecar — the one
piece of evidence that could have been recovered.
`has_invalid_sqlite_header_preopen` generalises the zeroed probe (zeroed is a
subset of "no SQLite header"; same live-connection contract, never raises).
`quarantine_invalid_state_db` moves the file AND its -wal/-shm aside as
`state.db.<zeroed|notadb>-<ts>-<pid>.bak` before anything opens it; a fresh
DB is created as before.
Re-authored on current main (the quarantine helpers moved to
hermes_state_dbfile.py in d15c61b5dc); one regression test proves the
notadb case is quarantined with its sidecars and the new DB passes
integrity_check.
Refs #102198 (the write-after-SIGTERM that clobbers page 0 is not addressed
here; this preserves the evidence instead of destroying it).
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