Replace key prefix matching (journal#j-, daily-, weekly-, monthly-)
with NodeType filters (EpisodicSession, EpisodicDaily, EpisodicWeekly,
EpisodicMonthly) for all queries: journal-tail, digest gathering,
digest auto-detection, experience mining dedup, and find_journal_node.
Add EpisodicMonthly to NodeType enum and capnp schema.
Key naming conventions (journal#j-TIMESTAMP-slug, daily-DATE, etc.)
are retained for key generation — the fix is about how we find nodes,
not how we name them.
Co-Authored-By: ProofOfConcept <poc@bcachefs.org>
804578b977