docs(reviewer): update audit status + add finding-orchestration plan

Session 1 (2026-05-31) resolved 26 findings across Sonnet/Haiku/Opus; 298/298
CGAL tests green.  Bring the audit docs in line with reality:

- README.md: G0 banner now records that the original authors were contacted by
  email about porting/relicensing rights (awaiting reply); headline-status cells
  updated per finding; new "Session 1 — implemented" record; link to the plan.
- Per-audit resolution banners (api-performance, numerical-stability,
  input-validation, test-coverage, math-citation, thread-safety) + G0-blocked
  banners (cgal-submission, dependency-license).
- NEW finding-orchestration.md: the meta-plan mapping every finding to a session,
  an implementing model (Haiku/Sonnet/Opus by the "how much must be understood"
  rule), and an Opus review gate after each implementation session.  Records S1
  (done) and lays out S2–S6 so the next session can be picked up cold.

Docs only — no code change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

doc/reviewer/api-performance-audit-2026-05-31.md

@@ -14,6 +14,12 @@ act on it without prior context. Each finding includes:
 
 Status legend: 🔴 Critical · 🟡 Important · 🔵 Hint / nice-to-have
 
+> **✅ Resolution status (2026-05-31, Session 1):** **A1–A3 ✅** (renamed with
+> `[[deprecated]]` aliases), **B1 ✅** both halves (HyperIdeal + Inversive-Distance
+> block-FD), **B2/B3/B4/B5 ✅** (folded into the `newton_core` refactor — see
+> test-coverage **H2**). **A4/A5 deferred** until the G0/G1 licensing outcome
+> (public CGAL surface). 298/298 tests green. Plan: [`finding-orchestration.md`](finding-orchestration.md).
+
 > **Companion documents (no overlap in findings):**
 > - `external-audit-2026-05-30.md` — port-faithfulness bugs
 > - `test-coverage-error-handling-audit-2026-05-31.md` — test gaps + error handling