[TEST] Add Contract Testing with Pact

[JoshuaAFerguson]

Objective

Implement contract testing to prevent API breaking changes.

Implementation

// Consumer test (UI):
pact.AddInteraction().
    Given("Session 123 exists").
    UponReceiving("A request for session details").
    WithRequest("GET", "/api/v1/sessions/123").
    WillRespondWith(200, map[string]string{
        "id": "123",
        "status": "running",
    })

Acceptance Criteria

• Pact consumer tests in UI
• Pact provider tests in API
• Contract verification in CI/CD
• Breaking changes detected

Files

• ui/tests/pact/ (NEW)
• api/tests/pact/ (NEW)
• .github/workflows/contract-tests.yml (NEW)

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity.

Action Required:

• If this issue is still relevant, please add a comment to keep it open
• If this is blocked, add the status:blocked label
• If this is no longer needed, it will be closed in 7 days

[github-actions]

This issue was automatically closed due to inactivity.

If you believe this was closed in error, please reopen it with a comment explaining why it should remain open.