Add billing customer consolidation guard

[haki203]

Summary

• Adds a distinct billing-customer-consolidation-guard/ Revenue Infrastructure slice for issue Revenue Infrastructure #20.
• Evaluates duplicate billing/customer profiles inside one institution before subscriptions, AI compute credits, analytics license seats, invoices, tax identities, and payment evidence are consolidated.
• Blocks legal/tax identity conflicts, routes duplicate active subscriptions and risky credit transfers to finance review, preserves open receivables, and emits a survivor-account draft.
• Includes deterministic JSON, Markdown, SVG, and MP4 reviewer artifacts from synthetic data only.

Non-overlap

This is not another generic billing ledger, metering module, payment webhook/failover guard, dispute guard, tax/FX/proration module, procurement or invoice-acceptance gate, account-transfer guard, collections flow, storage overage guard, trial/promotion guard, prepaid credit breakage guard, analytics API/seat roster module, or compute idempotency guard. It focuses specifically on duplicate billing customer consolidation inside the same institution.

Validation

• node --test billing-customer-consolidation-guard/test.js -> 3 tests passed
• FFMPEG_PATH=<local ffmpeg-static binary> node billing-customer-consolidation-guard/demo.js -> generated JSON/Markdown/SVG/MP4 reviewer artifacts
• node --check billing-customer-consolidation-guard/index.js
• node --check billing-customer-consolidation-guard/sample-data.js
• node --check billing-customer-consolidation-guard/demo.js
• node --check billing-customer-consolidation-guard/test.js
• ffmpeg -v error -i billing-customer-consolidation-guard/reports/demo.mp4 -f null - -> decoded without errors
• git diff --cached --check

Synthetic data only. No credentials, private customer data, payment processor calls, bank/ACH/wallet actions, Stripe, PayPal, ERP, SSO, SCIM, accounting, payout systems, or live billing systems are used.

/claim #20