Follow-up on the salvaged #111034:
- `_start_multiplex` published the enumerated home list before the gate had
filtered it, so a raising `profile_gate` (the Desktop stand-down probe from
#100489) kept the thread alive but ticked every profile UNGATED — racing the
gateway that owns them for the same cron store. The list is now assigned only
after gating; a gate failure yields zero ticks for that cycle.
- `cron/scheduler_thread.py::SupervisedTickerThread` wraps the gateway ticker
thread; `_start_gateway_housekeeping` gets a per-tick "Cron ticker supervisor"
chore that respawns a ticker that ended without a stop request and logs the
outage at ERROR. Every guard inside `start()` keeps the loop alive, but nothing
outside it could notice a thread that had already ended.
- Tests trimmed to the invariants, proven red on origin/main: a REAL corrupt
`executions.db` (no patched recover) no longer kills the ticker; a raising gate
keeps the thread alive with zero ticks; housekeeping restarts a dead ticker and
leaves a stopped one alone.
Root cause: the unguarded pre-loop `recover_interrupted_executions()` +
`record_ticker_heartbeat()` were added by d9dd05b69d (#61791, "truthful
execution ledger", 2026-07-09). The reporter's build (e440bf35) also carried
#107485's `completed_occurrence()` in the due scan, which opens the same ledger
on every tick — the first traceback in their errors.log is that in-loop hit
(caught); the restart then hit the SAME corrupt ledger from the pre-loop
recovery scan, which nothing caught: thread dead, no heartbeat, no error marker.
teknium1