Retain actual signed bank master statement cash and physical custody DVP

Verified non-API-key exact configured service with ledger:securities:bridge required. Signed DVP binds the exact actual execution, full physical units, cash amount, reviewed external master account and actual bank statement identifier/line, plus actual cash/delivery documents and dates. Native ledger accounting and state commit atomically; permanent exact-source protection refuses generic reversal or receipt reuse. Late evidence retains actual dates and contractual original yield. Provider signature alone does not establish independent bank-statement reconciliation. All mutations require verified authority even in local mode; customers and API keys are refused. Evidence JSON is strict and bounded at 5 MiB; complete responses are bounded at 16 MiB and never silently truncated.