Complete the Reserves ledger feature

Summary

Completed the Reserves feature across foundation, split deposits, Income integration, reserve-only spending, transfers, archival lifecycle, income conversion, move-to-income, funded cash expenses, and release hardening.

Decisions

• Kept reserve operations and entries isolated from normal transactions except for explicitly generated income and expense rows
• Used deterministic reserve locking and derived balances for overdraft-safe atomic mutations
• Protected generated normal transactions through operation links and compound deletion
• Presented reserve activity with explicit source and nature discrimination so direct deposits never count as normal income

Learnings

• Cross-tab refresh coordination and stale selector coverage need dedicated end-to-end verification alongside feature tests
• Operation history policy must account for current reserve balances and archived state, not only operation type