ADR-015: streams depth — carried-metadata keys, global-FIFO ordering, StreamEvent, trim_to (OQ-12 resolved)

docs/architecture/overview.md

@@ -77,6 +77,8 @@ Per [ADR-002](decisions/002-feature-scope.md):
 | [011](decisions/011-sqlite-substrate-fork.md) | SQLite substrate — fork honker-core into owned code | Accepted |
 | [012](decisions/012-forked-substrate-design.md) | Forked substrate design (contract-blind boundary, fidelity, port deltas) | Accepted |
 | [013](decisions/013-fold-substrate-into-sqlite.md) | Fold the forked substrate into `alkstore-sqlite` (no fourth crate) | Accepted |
+| [014](decisions/014-outbox-tx-enqueue.md) | Transactional outbox enqueue (`outbox_enqueue_tx` on `TxHandle`) | Accepted |
+| [015](decisions/015-streams-depth.md) | Streams depth (carried-metadata keys, global-FIFO ordering, `StreamEvent`, `trim_to`) | Accepted |
 
 ## Non-goals