ADR-003: Append-Only Ledger with Wallet Projection

Status

Accepted

Context

Economic events need immutable history while mobile clients need fast balance reads.

Decision

Use append-only points_ledger as source of truth and keep points_wallet as a derived projection/cache. Corrections are posted as compensating entries, never in-place mutation.

Consequences

• Strong auditability and rollback safety.
• Requires projection consistency checks and drift alerts.
• Slightly higher implementation complexity than balance-only models.