docs(roadmap): add phase orchestration system mirroring the reviewer audit workflow

Brings doc/roadmap/ to the same operational level as doc/reviewer/ by adding
the two missing structural files and updating existing docs to close the gap
identified in the system review.

New files:
- doc/roadmap/phase-orchestration.md  — master phase table (model assignments,
  session IDs, status, review-gate checklist); mirrors finding-orchestration.md
- doc/roadmap/session-prompts.md      — copy-paste-ready prompts for P1–P4
  (Haiku/Sonnet/Opus) + universal Opus review gate; mirrors reviewer/session-prompts.md

Updated files:
- CLAUDE.md: roadmap section now lists porting-status.md, phase-orchestration.md,
  session-prompts.md; reviewer section adds finding-orchestration.md and
  session-prompts.md; agentic-workflow section has direct "S3 is next / P1 is next"
  entry points so agents don't need to derive the next action from scratch
- doc/roadmap/phases.md: Current-focus table at the top (7 tracks, next session
  per track, gating); cross-links to geometry-central-comparison.md,
  software-landscape.md, complexity.md added in GC and 9b-analytic sections
- doc/roadmap/porting-status.md: snapshot date updated to 2026-05-31 (post S1+S2);
  test count replaced by reference to doc/api/tests.md; §4 gains four new solver
  rows (newton_core refactor, NewtonStatus enum, diagnostics, selectable clamp mode);
  §7 gains four new research-extension rows from S1/S2
- doc/roadmap/research-track.md: header companion-docs section links to
  novelty-statement.md, software-landscape.md, and phase-orchestration.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

doc/roadmap/phases.md

@@ -10,6 +10,26 @@
 
 ---
 
+## ◼ Current focus (as of 2026-06-01)
+
+> **Agent entry point.** Read this box first. For model assignments, priority
+> order, and ready-to-paste prompts, see
+> [`phase-orchestration.md`](phase-orchestration.md) and
+> [`session-prompts.md`](session-prompts.md).
+> Audit-finding sessions run in parallel from `doc/reviewer/`.
+
+| Track | Next session | Gating |
+|---|---|---|
+| **Audit findings** | S3: H3/H4/H5/V5/V6 — Sonnet → Opus review | None — start now |
+| **Phase quick-wins** | P1: 9g.1 + 9h.1 + 9h.2 + 9d.3 — Haiku → Opus review | None — start now |
+| **Research: Decorated DCE** | P2: Phase 12 — Sonnet → Opus review | None — start now |
+| **Circle pattern + convergence** | P3: 9e + 9d.4 + 9g.2 — Sonnet → Opus review | None — start now |
+| **Research: Analytic Hessian** | P4: Phase 9b-analytic — Opus | ⏸ awaiting reviewer Q3 |
+| **Java port: genus > 1** | P5: Phase 9c — Opus | ⏸ awaiting reviewer Q4 + G0 |
+| **CGAL packaging** | S6 (audit system) — Opus | ⛔ blocked on G0 (author reply pending) |
+
+---
+
 ## ◼ Porting complete — Phases 1–7
 
 ```
@@ -107,14 +127,16 @@ mesh type.
          Status: 🟡 PR #9 open, 7 tests passing, ~96× speed-up measured.
 
 9b-analytic   Full analytic HyperIdeal Hessian via Schläfli identity
-         → planned, see research-track.md
+         → planned, see research-track.md + session-prompts.md §P4
          Mathematical source: Springborn 2020 §4 + Schläfli 1858/60
                               + Rivin, Schlenker 1999 "The Schläfli formula in
                                 Einstein manifolds with boundary" (ERA-AMS 5, 18–23)
                               + Cho-Kim 1999 + Glickenstein 2011 §4
          Algorithm: explicit chain rule through (bᵢ,aₑ) → ℓᵢⱼ → ζ₁₃/ζ₁₄/ζ₁₅ → αᵢⱼ/βᵢ
-         Includes: short LaTeX correctness note in doc/math/.
+         Includes: 805-line LaTeX derivation in doc/math/hyperideal-hessian-derivation.md.
          Effort: 10–14 days net.  Trigger: profiling on V > 5000.
+         Complexity / scaling context: doc/math/complexity.md.
+         ⏸ GATED: awaiting reviewer Q3 answer ("worth ~2 weeks at your mesh sizes?").
 
 9c — Genus g > 1 fundamental domain  (Java port + research extensions)
 ──────────────────────────────────────────────────────────────────────
@@ -414,6 +436,11 @@ poor input triangulations. Both share the same
 mathematical core (discrete conformal equivalence, Gauss–Bonnet,
 variational principle of Bobenko–Springborn 2004).
 
+Full architecture-level comparison (overlap analysis, adoption rationale,
+scientific value): [`doc/architecture/geometry-central-comparison.md`](../architecture/geometry-central-comparison.md).
+Software landscape (libigl, CGAL, pmp-library, geometry-central):
+[`doc/math/software-landscape.md`](../math/software-landscape.md).
+
 ---
 
 ## ◼ Phase 10 — Genus g ≥ 2 (research with partial Java support)