Wire trade order test endpoint into TradeService

[jacog2]

PAID Ticket rules

Price: 10$

README source

• Section: Trade Interface
• Feature: - [ ] Trade order test

Description
The endpoint class exists, but the public TradeService test-order method should execute the test endpoint and be covered.

Acceptance criteria

• Endpoint, stream event, or subscription class is described for this feature
• The appropriate client service or socket API exposes the feature
• The feature is exported where consumers need public access
• Unit tests cover request shape, service/socket dispatch, or event parsing as applicable
• README feature status is updated when implementation is complete

Created from #26 to track currently unchecked README functionality.

[suihan253561554]

Implemented in PR #113: #113

Verification included in the PR:

• npm run build
• targeted TradeService tests
• npm run lint