Complements ec0227b43 (context-scoped cron store): the ContextVar override
is the right tool for deliberate cross-profile scoping, but with no
override active, _current_cron_store() returned the import-time constants —
so a HERMES_HOME set AFTER cron.jobs import (the filed incident: test
fixtures patching the env too late) still read/wrote the user's real
jobs.json. The fallback now resolves the active profile home fresh via
get_hermes_home() (context-local override, then env) and scopes the store
to it; when the home is unchanged since import, the exact module-level
constants are returned as before (zero change in the common path, and they
remain the documented compatibility surface). use_cron_store() still wins.
Three tests: late env repoint scopes the store; unchanged home returns the
import-time constants identically; an active use_cron_store() override
beats the env.
slow4cyl
5c121f157f