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/numerical-stability-audit-2026-05-31.md

@@ -10,6 +10,13 @@ port-faithfulness (`java-port-audit.md`) and from internal error propagation
 
 Status legend: 🔴 Critical · 🟡 Important · 🔵 Polish
 
+> **✅ Resolution status (2026-05-31, Session 1):** **N3 ✅** (selectable clamp mode
+> `HardJava`|`SmoothBarrier`), **N4/N6 ✅** (named `constexpr` constants), **N5 ✅**
+> (Kahan stable triangle area). **N1 ✅\*** largely subsumed by the B1 block-FD
+> Hessian; the remaining FD-step/tol coupling note folds into **N2**. **N2** (tolerances.md)
+> and **N7** (conditioning diagnostic) **open** — scheduled S2/S4 in
+> [`finding-orchestration.md`](finding-orchestration.md). 298/298 tests green.
+
 > **Relationship to existing audits:** `java-port-audit.md` already verified several
 > per-formula numerical edge cases (degenerate triangles #1, overflow centring #10).
 > This audit takes the *cross-cutting* view those miss: how the tolerances relate to