Add one end-to-end contract-style workflow test

[fleuronvilik]

Objective

Add a contract-style test that validates a full business workflow.

Scope

• Cover: create DeliveryRequest, approve, deliver, submit SalesReport, void report.
• Validate state transitions and PartnerInventory outcomes.

Acceptance Criteria

• Single scenario test validates full workflow behavior.
• Includes at least one invalid branch asserting typed error.
• Test remains deterministic and readable.

Why

End-to-end tests protect behavior across Domain, Policy, App, and Persistence layers.