Flatten the store to {href: [codes]}. One href carries one LEARNABLE
rule, so keying the codes by the rule's supported field too let the
write side (rule.supported_field) and both read sides (the module-level
SUPPORTED_FIELD) disagree the moment a rule used a different field --
codes learned and persisted, then never offered.
The options flow's reset step read the persisted value raw in the
entry-not-loaded branch, so malformed data aborted the one screen that
can clear it; route it through LearnedModes like every other reader.
For the same reason forget_learned_modes() now persists whenever the
entry carries a record, not only when the in-memory store had one: a
record _coerce rejected at startup exists only on the entry.
Marc Billow
4f3bdde6e5