ADR-012: forked-substrate design — contract-blind boundary, fidelity posture, port deltas

Follow-through on OQ-06/ADR-011: pin the fork's structural decisions
(alkstore-substrate as a vendored path-dep crate, contract-blind API
boundary with contract formulas computed engine-side and pinned
equivalent by the contract suite, keep-the-kept-half API fidelity for
cheap cherry-picks, the W-1/W-2/dead-man's-switch/W-4 port deltas
decided per item, bootstrap re-keying off error-string matching, no
rename migration, deliberate upstream tracking).

Consistency sweep across the doc set for the fork: annotate ADR-003/
005/009/010 and core-contract for superseded ownership facts, fix
schedule-storage table naming (ADR-009 §5, queues.md), re-key ADR-010
§6's notifications hygiene to the at-attach cap the fork scope
realizes, add OQ-11 (scaffold-time residue), and complete both ADR
indexes. Independent review: 0 critical, warnings addressed.

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, honker-core |
+| `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-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 honker-core/rusqlite |
+| [engine-sqlite.md](engine-sqlite.md) | SQLite engine: mapping the contract onto the forked substrate (`alkstore-substrate`)/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) |
@@ -66,7 +66,7 @@ Per [ADR-002](decisions/002-feature-scope.md):
 |---|---|---|
 | [001](decisions/001-crate-split.md) | Reactive-core + per-engine crates | Accepted |
 | [002](decisions/002-feature-scope.md) | Feature scope (inventory-confirmed) | Accepted |
-| [003](decisions/003-sqlite-driver.md) | SQLite: rusqlite + honker-core, bridged seam | Accepted |
+| [003](decisions/003-sqlite-driver.md) | SQLite: rusqlite + honker-core lineage, bridged seam (ownership: ADR-011) | Accepted |
 | [004](decisions/004-postgres-driver.md) | Postgres: tokio-postgres + deadpool, hand-rolled LISTEN | Accepted |
 | [005](decisions/005-dependency-ownership.md) | Published libraries by default, named fork triggers | Accepted |
 | [006](decisions/006-wake-and-delivery-contract.md) | Opaque wake + re-read; notify-vs-streams guarantee split | Accepted |
@@ -74,6 +74,8 @@ Per [ADR-002](decisions/002-feature-scope.md):
 | [008](decisions/008-contract-v1-pinning.md) | Contract v1 surface pinning (partition, TxHandle shape, wake type, reserved strings, error taxonomy) | Accepted |
 | [009](decisions/009-scheduler-collapse.md) | Scheduler collapse (queues + `schedule()`, `@every`-only) | Accepted |
 | [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 |
 
 ## Non-goals