Implementation plan: wave-based decomposition; waves 1-2 decomposed (11 tasks)

docs/plans/implementation.md records the wave structure (core ->
substrate fork || pg engine -> sqlite engine -> contract suite ->
release), the decided points (contract-suite layout = option (a),
engine-tests vs equivalence-suite split, no CI, mem-engine/fuzzing
deferrals surfaced), and the review-gate rhythm.

Wave 1 (foundations): workspace scaffold, core errors/validation,
value types, trait surface, contract-suite scaffold (+ADR-022),
review gate.
Wave 2 (substrate fork): fork scaffold/provenance, connection+watcher
port, queue-op re-derivation on contract v1, provenance/floor close,
review gate.

tasks/fork-substrate-scaffold.md

@@ -0,0 +1,60 @@
+---
+id: fork-substrate-scaffold
+name: Fork scaffold — substrate subtree, provenance register, licenses
+status: pending
+depends_on: [scaffold-workspace]
+scope: narrow
+risk: low
+impact: component
+level: implementation
+tags: [wave-2, substrate]
+---
+
+## Description
+
+Create the fork's home and its provenance apparatus before any code
+moves (ADR-011, ADR-012 §1 as amended by ADR-013, ADR-018):
+
+- `alkstore-sqlite/src/substrate/` module subtree, wired into the
+  engine crate's module tree (`mod substrate;` — internal, never
+  re-exported through the engine's public API; ADR-012 §2's
+  contract-blind boundary starts structurally).
+- `PROVENANCE.md` at the subtree root per ADR-018: upstream identity
+  (honker-core, checkout `/workspace/honker` @ `f4e53c6`, package
+  `node-v0.5.1-10-gf4e53c6`), license (MIT OR Apache-2.0), the fork
+  decision citation (ADR-011), and the empty delta register structure
+  (per-delta, category-tagged entries — the categories ADR-018 pins;
+  the port deltas of `fork-port-deltas` are the first entries).
+- The dual-license notice carried in-tree (MIT OR Apache-2.0 text, per
+  ADR-012 §1's scaffold-time list).
+- The substrate's `Cargo.toml`-independent posture: the subtree
+  compiles as engine-crate modules; its dependencies (rusqlite) come
+  from the engine crate's manifest.
+
+This task moves no machinery — it establishes where the fork lives,
+who it is, and how its lineage is tracked, so the port tasks land into
+a finished frame.
+
+## Acceptance Criteria
+
+- [ ] `src/substrate/` exists, wired as an internal module, empty or
+      stub content only
+- [ ] `PROVENANCE.md` complete per ADR-018 (identity, revision,
+      license, decision citation, delta-register structure)
+- [ ] Dual-license notice in-tree
+- [ ] Engine crate still compiles; clippy/fmt clean
+
+## References
+
+- docs/architecture/decisions/011-sqlite-substrate-fork.md
+- docs/architecture/decisions/012-forked-substrate-design.md §1
+- docs/architecture/decisions/013-fold-substrate-into-sqlite.md
+- docs/architecture/decisions/018-provenance-register-and-cherry-picks.md
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion