Fintech ledger — verified starter stacks

Every stack below uses Fintech ledger. Each one's init code, migration schema, and connection pooling was compiled and tested by our verification pipeline against current versions — and re-verified whenever Fintech ledger or a companion dependency ships a release. That maintenance is the point: these configs stay correct as the ecosystem drifts.

• Double-entry ledger schema: accounts, journal entries & lines
• Double-entry ledger schema: accounts, journal entries & lines