feat(provenance): v0.0.18 mock runtime integration tests E2E — 9 scenarios canonical own fixtures

Phase 2.1 PROVENANCE pallet — 9 integration tests E2E via FRAME mock runtime
composition (`construct_runtime!` macro + derive_impl + sp_io::TestExternalities).
Cierra honest disclosure sesión 2 ("real chain runtime aún NO arranca"). Pallet
end-to-end validado canonical sin esperar Slice 2e WASM resolution structural.

## 9 integration tests canonical PROV-3 flow

5 scenarios:
- scenario_1_passed_info_anchored_canonical (PROV-2/3/7) ✅
- scenario_2_warning_anchored_canonical (PROV-2/3/6/7) ✅
- scenario_3_failed_critical_rejected_canonical (PROV-6) ❌ NotAnchorable
- scenario_4_passed_block_security_rejected_canonical (PROV-6) ❌ NotAnchorable
- scenario_5_anonymous_level_0_rejected_canonical (PROV-5) ❌ ValidatorTierInsufficient

4 additional:
- additional_idempotency_already_attested_rejected_canonical (PROV-2) ❌ AlreadyAttested
- additional_tampered_signature_rejected_canonical (PROV-4) ❌ InvalidSignature
- additional_tampered_payload_rejected_canonical (PROV-4) ❌ InvalidSignature
- additional_6_step_prov_3_walkthrough_canonical (PROV-3 full) ✅ Pre/post assertions

## Own fixtures canonical

Per audit canonical sesión 3+ (docs/L7_roadmaps/AUDIT_CHARON_SESION_3_STATE_V1.md),
Ergon E2E fixture diary claim aspirational sin shipped commit verified — filesystem
+ git history confirma no source file canonical. Charon construye own fixtures
basados en vendor copy ValidationAttestation real existente. Pattern análogo
Slice 3 mock-WASM + v0.0.16 Ed25519 interim encoding.

## Files canonical

- NEW: crates/origin-chain-provenance/src/mock.rs (75 LOC mock runtime)
- NEW: crates/origin-chain-provenance/src/tests_integration.rs (270 LOC, 9 tests)
- EDIT: crates/origin-chain-provenance/Cargo.toml (sp-core+sp-io+sp-runtime dev-deps)
- EDIT: crates/origin-chain-provenance/src/lib.rs (mod mock + mod tests_integration + docstring v0.0.18)
- EDIT: CHANGELOG.md (v0.0.18 entry canonical pattern Phase 2.1)

## Verification

- cargo test -p origin-chain-provenance — 17 tests verde, 0 failures
  (9 integration + 6 standalone Ed25519 + 2 auto-generated)
- Workspace tests no regressions
- Cero warnings críticos

🎉 Phase 2.1 PROVENANCE pallet validated E2E via mock runtime canonical.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/origin-chain-provenance/Cargo.toml

@@ -28,6 +28,14 @@ ed25519-dalek = { workspace = true }
 parity-scale-codec = { workspace = true }
 scale-info = { workspace = true }
 
+[dev-dependencies]
+# Mock runtime canonical para integration tests v0.0.18 — PROV-3 E2E flow.
+# Per pallet Substrate convention: sp-io TestExternalities + sp-runtime
+# AccountId32 + frame_support construct_runtime macro.
+sp-core = { workspace = true, default-features = true }
+sp-io = { workspace = true, default-features = true }
+sp-runtime = { workspace = true, default-features = true }
+
 [features]
 default = ["std"]
 std = [