[#548] Add bounded charge reconciliation

[Jagadeeshftw]

Summary

Adds a callable, side-effect-free reconciliation job that detects charge ledger drift and returns a deterministic operator report.

What changed

• Defines explicit amount, capture/refund, lifecycle-status, identifier, and duplicate-ID invariants.
• Exposes individually testable checkChargeInvariants checks and a runChargeReconciliation job entry point.
• Scans iterables in bounded chunks without materializing an unbounded dataset.
• Reports scan limits, truncation, violation counts, offending IDs, stable invariant codes, and reasons.
• Keeps scans idempotent and non-mutating; no automatic remediation is performed.
• Adds typed ChargeReconciliationError handling for invalid scan options.
• Adds unit and store-to-job integration coverage for clean data, amount imbalance, status drift, large datasets, deterministic ordering, duplicate IDs, repeated scans, and non-mutation.
• Documents the charge model, invariants, bounds, report contract, and operational guidance.

Verification

• npm run build
• npm run lint
• node --test dist/chargeReconciliation.test.js dist/chargeReconciliation.integration.test.js (13 passing tests)

Closes #548