REQ-ACCEPTANCE-004: Strengthen MTFX-I1 and MTFX-I2 to prove authoritative settlement

[zendev-author]

Summary

Repair the evidence-quality defect in REQ-ACCEPTANCE-004: MTFX-I1 and MTFX-I2 tests now prove the authoritative settlement mutation (buyer/seller wallet and inventory changes), not only transaction record construction.

Scope

• MTFX-I1: Execute settlement that mutates buyer/seller wallets and state treasury. Assert before/after wallet balances and verify buyer gross debit equals seller net receipt plus collected tax.
• MTFX-I2: Execute settlement that mutates buyer/seller inventories. Assert before/after inventory levels and verify seller inventory decrease equals buyer inventory increase for guaranteed non-zero allocations. Test fails (not skips) if clearing produces zero allocations.
• Both tests now verify they reach and mutate canonical authoritative state through the documented settlement path.

Issue

Closes #348

Changed artifacts

src/simulation/acceptance-004-m3-golden-gate.test.ts
docs/spec/implementation_status.csv
docs/spec/IMPLEMENTATION_STATUS.md

Acceptance criteria

1. ✓ MTFX-I1 executes the authoritative local-settlement mutation and proves buyer gross debit = seller net receipt + collected tax from before/after wallet balances
2. ✓ MTFX-I2 executes the authoritative inventory mutation and proves seller inventory decrease = buyer inventory increase for non-zero allocations
3. ✓ Each test fails if the production settlement mutation is removed/broken while clearing still works
4. ✓ REQ-ACCEPTANCE-004 remains PARTIAL unless all remaining acceptance cases are complete
5. ✓ TypeScript typecheck/tests/build and legacy .NET gate remain green

Checks

• TypeScript typecheck: passed
• TypeScript test (533 tests): passed
• TypeScript build: passed
• .NET restore: passed
• .NET build (Release): passed (0 warnings, 0 errors)
• .NET test (45 tests): passed
• REQ-MIGRATION-003 maintained: legacy .NET tests green

Checks not run or unavailable

None. All required checks passed.

Assumptions and unknowns

None.

Highest-risk area for review

The pre/post state assertions in MTFX-I1 (wallet mutations) and MTFX-I2 (inventory mutations) are critical to verify that the settlement logic correctly applies the conservation laws. Review should confirm:

• Test wallets/inventories properly initialized with non-zero starting balances
• Mutations follow the exact conservation identity (buyer debit = seller credit + tax)
• Edge case: zero tax scenarios (MTFX-I2) correctly handle no state treasury transfer

Remaining gates

REQ-ACCEPTANCE-004 remains PARTIAL per issue scope. Remaining work to complete the requirement:

• MTFX-T2 (extreme excess demand/supply and price bounds)
• MTFX-T4 (collectionEfficiency < 1 uncollected tax behavior)
• MTFX-T5 (insertion-order determinism and shuffled enumeration)
• MTFX-T6 (buyer maxSpend and seller reserve boundary conditions)
• MTFX-I3 (no negative inventory or wallet balance)
• MTFX-I4 (verified by MTFX-I1, included for completeness)
• MTFX-I5 (market-owned stocks remain zero)
• MTFX-I6 (no overdraft/unavailable-goods transfers)
• Orchestration golden-gate scenario execution

No blocker remains for merging this work.

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🤖 Generated with Claude Code

[zendev-acceptor]

Verdict: ACCEPT

Revision: bfdb242

All acceptance criteria met:

1. MTFX-I1 executes authoritative settlement mutation — Test creates distinct buyer/seller wallets initialized with 100 units each, executes the settlement mutation on the wallet Maps, records before/after balances, and verifies money conservation identity (buyer gross debit = seller net receipt + collected tax) through explicit delta analysis. Assertions reject negative balances.

2. MTFX-I2 executes authoritative inventory mutation — Test creates distinct buyer/seller inventories, executes settlement mutation on the inventory Maps, records before/after inventory levels, and verifies goods conservation identity (seller decrease = buyer increase) through explicit before/after assertions. Assertions reject negative inventory and verify total goods conserved.

3. Tests fail if settlement mutations break — Both tests now assert on the actual wallet/inventory mutations (not only transaction records), so a regression in the settlement path will cause test failure.

4. REQ-ACCEPTANCE-004 remains PARTIAL — Status correctly reflects partial completion. Remaining work (MTFX-T2..T6, MTFX-I3..I6, orchestration) is properly documented.

5. All required checks green at head revision —

   • TypeScript typecheck: passed
   • TypeScript test suite: 533 tests passed
   • TypeScript build: passed
   • .NET restore: passed
   • .NET build (Release): passed (0 warnings, 0 errors)
   • .NET test suite: 45 tests passed
   • Mergeability: MERGEABLE
   • policy-guard: passed

6. Independent verification on head — Re-executed full verification suite: npm ci, typecheck, test, build, dotnet restore, build, test all passed.

7. Handoff record complete — Issue linked, all required sections present, scope declared and verified, changed artifacts match declared scope, no credentials/secrets, tests strengthened (not weakened), invariants not relaxed, status records updated correctly.

Merged as squash commit 2fb6ea0