[P1.5-S5-ARI-35] Ground truth file (`tests/acceptance/ground_truth.json`)

[bjridicodes]

Ticket: P1.5-S5-04

Type: Test Data | Est: 0.5d

Goal: Machine-readable expected outcomes for all 30 incidents so AC-01 through AC-06 can be scored automatically.

Scope:

• tests/acceptance/ground_truth.json (new): array of 30 objects, one per incident
• Schema per entry:

  {
    "incident_number": "INC0020001",
    "uc": "uc1|uc2|uc3",
    "expected_platform_tag": "cdp|gcp",
    "expected_error_class": "oom|disk|auth|network|pipeline|unknown",
    "expected_affected_ci": "cdp-nn-01",
    "logs_available": true
  }

• logs_available=false for all 10 UC3 entries (round 2 graceful degradation)
• logs_available=true will be set for UC3 entries before S6 round 3 execution

Acceptance criteria:

• Exactly 30 entries (10 per UC)
• Every entry has all 6 required fields populated with valid values
• All UC3 entries have logs_available: false
• JSON is valid and parses without error