ADR-013: fold the forked substrate into alkstore-sqlite — no fourth crate

Operator review of ADR-012's fork design re-litigated §1's crate
identity. alkstore-substrate misdescribed what the code is (unpublished,
path-dep-only, one consumer, SQLite-only — not a family-wide substrate);
the mechanical-diff hope was gone at fork time regardless (port deltas,
renames, re-derived half); and the alksocks F-1 lesson applies — a
vendored region under a second, weaker instruction set is a defect seam.
The fork folds into alkstore-sqlite as a bounded module subtree
(src/substrate/); ADR-012 §3–§6 retained verbatim, §2 retained with its
enforcement re-sited from the crate graph to diff fence + review +
contract-suite equivalence pins. OQ-11 item (1) dissolved.

docs/architecture/overview.md

@@ -29,7 +29,7 @@ Per [ADR-001](decisions/001-crate-split.md):
 | Crate | Contents | Driver dependencies |
 |---|---|---|
 | `alkstore` (core) | trait surface, types, error model | none (capability flags, if ever, are OQ-08's to add) |
-| `alkstore-sqlite` | SQLite engine ([ADR-003](decisions/003-sqlite-driver.md)) | rusqlite, `alkstore-substrate` (the forked honker-core lineage — [ADR-011](decisions/011-sqlite-substrate-fork.md), designed in [ADR-012](decisions/012-forked-substrate-design.md)) |
+| `alkstore-sqlite` | SQLite engine ([ADR-003](decisions/003-sqlite-driver.md)) | rusqlite; the forked honker-core lineage rides in-tree as the engine crate's substrate module subtree ([ADR-011](decisions/011-sqlite-substrate-fork.md), designed in [ADR-012](decisions/012-forked-substrate-design.md), folded per [ADR-013](decisions/013-fold-substrate-into-sqlite.md)) |
 | `alkstore-postgres` | Postgres engine ([ADR-004](decisions/004-postgres-driver.md)) | tokio-postgres, deadpool-postgres |
 | (mem engine, optional) | test convenience, decided at implementation ([ADR-001](decisions/001-crate-split.md)) | none |
 
@@ -53,7 +53,7 @@ Per [ADR-002](decisions/002-feature-scope.md):
 | Doc | Purpose |
 |---|---|
 | [core-contract.md](core-contract.md) | The unified trait surface: mechanisms, delivery guarantees, tx seam, naming |
-| [engine-sqlite.md](engine-sqlite.md) | SQLite engine: mapping the contract onto the forked substrate (`alkstore-substrate`)/rusqlite |
+| [engine-sqlite.md](engine-sqlite.md) | SQLite engine: mapping the contract onto the forked substrate module/rusqlite |
 | [engine-postgres.md](engine-postgres.md) | Postgres engine: mapping the contract onto tokio-postgres/LISTEN |
 | [queues.md](queues.md) | Queue/scheduler/outbox semantics depth (ADR-009/ADR-010 resolved) |
 | [deployment.md](deployment.md) | Host capabilities, connection budgets, deployment matrix (OQ-08) |
@@ -76,6 +76,7 @@ Per [ADR-002](decisions/002-feature-scope.md):
 | [010](decisions/010-queue-semantics-depth.md) | Queue semantics depth (visibility, backoff, dead-letter, sweep, layout) | Accepted |
 | [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 |
 
 ## Non-goals