Feature — Order Placement API Endpoint

[coderkrp]

As a user,
I want a secure endpoint to place orders across brokers,
So that I can execute my strategies.

Acceptance criteria

• AC1: A POST endpoint is created at /api/v1/orders.
• AC2: The endpoint is protected by the API Authentication Middleware.
• AC3: The endpoint accepts a standardized OrderRequest payload.
• AC4: The endpoint delegates the request to the RequestOrchestrator.
• AC5: The endpoint returns a UnifiedResponse with the results from each broker.
• AC6: The endpoint meets the performance NFRs (median overhead ≤50ms).

Definition of Done

• Code implemented in a feature/fix branch
• Unit / integration tests added or existing tests updated
• Linting passed and code builds locally
• Docs / README updated if behavior changed
• PR opened and linked (Closes #<issue-number>)
• Manual QA steps verified (if applicable)