Add institutional invoice delivery assurance guard

[goodgoodclaw]

/claim #20

Summary

• Add a dependency-free institutional invoice delivery assurance guard for Revenue Infrastructure.
• Validate invoice delivery evidence after invoice generation and before AR aging, dunning, collections, or entitlement holds.
• Check billing email bounces, portal upload receipts, PO attachment state, invoice/PDF hash parity, issue/due date ordering, AP contact freshness, finance owner escalation, and accepted delivery routes.
• Emit release/retry/hold decisions plus JSON, Markdown, and SVG reviewer artifacts from synthetic data.

Non-overlap

This is scoped to invoice delivery assurance before AR aging starts. It does not duplicate quote approval, billing receipt privacy, institutional invoice collections, dunning entitlement holds, payment rails, procurement controls, revenue recognition, tax, or dispute workflows.

Verification

• python3 -m unittest institutional-invoice-delivery-assurance-guard/test_invoice_delivery_assurance_guard.py
• python3 institutional-invoice-delivery-assurance-guard/invoice_delivery_assurance_guard.py --sample --json institutional-invoice-delivery-assurance-guard/demo/report.json --markdown institutional-invoice-delivery-assurance-guard/demo/summary.md --svg institutional-invoice-delivery-assurance-guard/demo/graph.svg
• python3 -m py_compile institutional-invoice-delivery-assurance-guard/invoice_delivery_assurance_guard.py institutional-invoice-delivery-assurance-guard/test_invoice_delivery_assurance_guard.py
• git diff --check

Synthetic data only. No payment processors, private customer systems, ERP/AR platforms, bank data, wallet data, credentials, or external service calls are used.

AI-assisted with Codex; reviewed and verified locally.