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005/009/010 and core-contract for superseded ownership facts, fix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/README.md

@@ -37,7 +37,7 @@ pending architecture review and OQ resolution.
 |---|---|---|
 | [001](decisions/001-crate-split.md) | Reactive-core crate + per-engine crates | Accepted |
 | [002](decisions/002-feature-scope.md) | Feature scope — inventory-confirmed surface | Accepted |
-| [003](decisions/003-sqlite-driver.md) | SQLite engine — rusqlite + honker-core, bridged seam | Accepted |
+| [003](decisions/003-sqlite-driver.md) | SQLite engine — rusqlite + honker-core lineage, bridged seam (ownership: ADR-011) | Accepted |
 | [004](decisions/004-postgres-driver.md) | Postgres engine — 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) | Wake contract — opaque wake + re-read; notify-vs-streams split | Accepted |
@@ -45,6 +45,8 @@ pending architecture review and OQ resolution.
 | [008](decisions/008-contract-v1-pinning.md) | Contract v1 surface pinning — surface partition, `TxHandle` shape, wake type, reserved strings, error taxonomy | Accepted |
 | [009](decisions/009-scheduler-collapse.md) | Scheduler collapse — queues + `schedule()`/`run_schedules`, `@every`-only v1, boundary guarantee row | Accepted |
 | [010](decisions/010-queue-semantics-depth.md) | Queue semantics depth — visibility/renewal, backoff curve, dead-letter, no-stranded-rows sweep, schema 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 posture, port deltas | Accepted |
 
 ## Open Questions
 
@@ -59,6 +61,9 @@ in suggested resolution order (OQ-04, OQ-09, OQ-05, OQ-06 resolved):
   honker-core's lineage, queue ops re-derived on contract v1.
 - **OQ-08** (medium): capability-surface shape.
 - **OQ-10** (medium): contract versioning across engine crates.
+- **OQ-11** (medium): forked-substrate follow-through (scaffold-time
+  decisions — [ADR-012](decisions/012-forked-substrate-design.md)'s
+  residue).
 
 Resolved (kept with resolutions): OQ-01 (feature scope), OQ-02
 (crate split), OQ-03 (drivers), OQ-07 (extension surface cut),