org.cannadb.like

A lightweight engagement signal — the publisher's like of another CannaDB record. Likes are the polymorphic-subject pattern: one record type covers multiple subject collections via an additive allowlist on `subject`. For v1 the allowlist is `org.cannadb.strain` and `org.cannadb.review`. Future indexable record types (e.g., grows, lists) get added to the allowlist additively without a lexicon revision; consumers gracefully ignore likes pointing at unknown collections. The AppView aggregates likes per-subject into counts and trending signals; like records do not carry counts themselves. CannaDB's social-signal pattern is to add new lightweight engagement features by extending the `subject` allowlist before authoring a new record type — "is this a like with different display, or something genuinely new?"