[withrvr]

Phase 2 (feature 5 of 6): Cross-reference rules

What this adds

The five rules spanning two sheets: E002 (unknown customer reference, on
either invoices or payments), E003 (unknown invoice reference), E007
(payment-to-invoice customer mismatch — the flagship worked example from
MASTER_PLAN.md section 8 and QA_PREP.md Q11), E010 (payment before
invoice date, flag-only per README's documented assumption), and E014
(overpayment — beyond the assessment's required list, added because the
data called for it, QA_PREP.md Q5).

All 14 rules are now implemented and registered. Verified against dataset
A: 17 exception rows across all 14 codes, exactly matching RULES.md's
summary table.

Assessment requirement served

Covers the remaining required categories: "unknown customers/invoices,"
"customer mismatch," and "payment before invoice" — plus E014, added
beyond the brief.

Docs updated

• README.md (Phase 2's "Validation performed" section lands in PR6)
• ARCHITECTURE.md
• API.md
• RULES.md — all 14 entries now written, status line updated to
  "14/14 rules implemented"
• DEVELOPMENT.md
• CHANGELOG.md (Phase 2's entry lands in PR6)

Verification

cd backend && uv run pytest app/collections/tests -v
# 100 passed

uv run python -m app.collections.scripts.reference_summary
# still 15 overdue / Rs 1,202,000.00 / West heaviest -- Phase 2 explains
# exclusions, doesn't change Phase 1's numbers

# manual cross-check: every rule fires, 17 rows total, matches RULES.md
python -c "... exceptions_by_rule(...) ..." # E001-E014 all present, sums to 17

Known gaps carried to next phase

• test_coverage.py and test_reconcile.py (invoice-amount and
  payment-centric identities) land in PR6, along with the final
  RULES.md/README.md/CHANGELOG.md consistency pass and the
  v0.3.0 tag attempt.

---

Generated by Claude Code