Follow-up to the cherry-picked #102431 fix, addressing the review findings:
- The two real-helper scheduler tests ran the Linux-only helper unmarked
and failed on macOS/Windows; the surviving one is now `linux_only`.
- `_warn_scope_degraded_once` used a bare `os.getuid()` that tripped
scripts/check-windows-footguns.py --all (lint lane red). The remedy text
is now built once in the helper and passed into the warning, so the
"scope binary vanished" case no longer warns about a missing D-Bus.
- Tests trimmed to the invariant bar: degraded != in_process and warns
once (helper level); default config still Popens externally and
`require_restart_safe_scope: true` raises (scheduler level, real helper).
Dropped the stubbed duplicate, the standalone config-raise test and the
in_process half already covered by the existing passthrough test.
- `GatewayChildDispatch.reason` had no reader outside a test; removed.
- Both degrade branches share one local `_degrade(detail)`.
- The per-fire config read uses `load_config_readonly()` (no deepcopy)
with the same `except Exception` guard as the sibling
`failure_nudge_threshold` read, so a config error no longer escapes
the launcher.
- Kanban's no-run-id guard fails closed for any non-`in_process` mode
instead of matching one enum value.
- Rationale restated in six places collapsed to the helper docstring;
`cron.require_restart_safe_scope` documented in the cron user guide.
kshitijk4poor
f003e449be