[P1.5-S5-ARI-38] AC evaluation + round 2 acceptance report

[bjridicodes]

Ticket: P1.5-S5-07

Type: Execution | Est: 1d

Goal: AC-01 through AC-06 scored per incident; pass/fail report written with documented root cause for every failure.

Scope (depends on P1.5-S5-06 results):

• Score each AC by comparing results_round2.json against ground_truth.json
• AC-03 (log recall) scored as N/A for UC3 incidents
• Write tests/acceptance/report_round2.md:
  • Per-incident per-criterion pass/fail table (30 rows × 6 ACs)
  • Summary accuracy/latency stats per UC
  • Miss analysis: categorise failures by root cause (wrong platform tag, no logs returned, LLM classification error, latency breach)
  • UC3 graceful degradation quality section (partial notification rating)

Acceptance criteria:

• Report complete with per-incident breakdown for all 30 incidents
• AC-01 through AC-06 targets met on UC1 and UC2, or failures have a documented root cause and remediation path
• UC3 graceful degradation documented (pipeline success rate, notification quality)
• Report committed to main branch