docs: add phase roadmap with porting/research boundary to README and architecture doc

Structured the development roadmap into four blocks with an explicit
boundary marker separating direct Java ports (Phase 1–7) from
infrastructure (Phase 8), remaining porting (Phase 9), and new
research territory (Phase 10+).

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

doc/architecture/overall_pipeline.md

@@ -471,6 +471,79 @@ This mirrors exactly the contract table in this document.
 
 ---
 
+## Development Roadmap
+
+> **Grenze Portierung / neue Forschung:**  
+> Phase 1–7 sind direkte Portierungen aus dem Java-Original (Sechelmann 2016).  
+> Ab Phase 8 geht die Arbeit über den Umfang der Java-Bibliothek hinaus.  
+> — Phase 8 (CGAL-Paket) ist **Infrastruktur**, kein neuer Algorithmus.  
+> — Phase 9 (Inversive-Distance, Analytischer Hessian, 4g-Polygon) ist **Portierung** ausstehender Java-Features.  
+> — Phase 10+ ist **eigenständige Forschung**, die über das Java-Original hinausgeht.
+
+---
+
+### ◼ Portierungsphase abgeschlossen — Phase 1–7
+
+```
+Phase 1   Clausen / Lobachevsky / ImLi₂                             ✅
+Phase 2   Hyper-ideal Geometrie (ζ, lᵢⱼ, αᵢⱼ, σᵢ)                 ✅
+Phase 3   CGAL-Infrastruktur + alle drei Funktionale (E/S/H)         ✅
+Phase 4   Newton-Solver (SimplicialLDLT + SparseQR-Fallback)         ✅   68 Tests
+Phase 5   Priority-BFS-Layout + CLI + JSON/XML                       ✅   95 Tests
+Phase 6   Gauss–Bonnet, Tree-Cotree-Schnittgraph, Normalisierung     ✅  121 Tests
+Phase 7   MobiusMap, halfedge_uv, Möbius-Holonomie, Periodenmatrix,
+          Fundamentalbereich (Genus 1), Java-Parität abgeschlossen   ✅  158 Tests
+```
+
+---
+
+### ◼ Infrastruktur (über Java-Bibliothek hinaus) — Phase 8: CGAL-Paket
+
+```
+8a   Traits-Klasse & Konzepte          → include/CGAL/Conformal_map_traits.h
+8b   Öffentliche CGAL-Header-Hierarchie → include/CGAL/Discrete_conformal_map.h etc.
+8c   Dokumentation im CGAL-Stil         → doc/Conformal_map/PackageDescription.txt
+8d   CGAL-Testformat                    → test/Conformal_map/
+8e   Declarative YAML-Pipeline          → pipeline validator (require/provide tokens)
+```
+
+See the [Declarative pipeline](#declarative-pipeline-target-for-phase-8) section above
+for the YAML schema that Phase 8e will validate at runtime.
+
+---
+
+### ◼ Ausstehende Portierung (Java-Features noch nicht übertragen) — Phase 9
+
+```
+9a   Inversive-Distance-Funktional (Luo 2004)
+       → InversiveDistanceMaps + functional + Hessian
+       → discrete uniformization via inversive distances
+9b   Analytischer HyperIdeal-Hessian (ζ-Kette)
+       → replace FD Hessian in hyper_ideal_hessian.hpp
+       → reduces Newton iterations for large meshes
+9c   4g-Polygon-Randlauf (Genus g > 1)
+       → extend compute_fundamental_domain() beyond genus 1
+       → algorithm outline already in fundamental_domain.hpp as TODO(Phase 9)
+```
+
+---
+
+### ◼ Neue Forschung (über das Java-Original hinaus) — Phase 10+
+
+```
+Phase 10   Globale Uniformisierung Genus g ≥ 2
+10a  Holomorphe Differentiale auf diskreten Flächen
+       → discrete harmonic 1-forms; integration along cut graph cycles
+10b  Siegel-Periodenmatrix Ω ∈ H_g  (g×g komplex-symmetrisch, Im(Ω) > 0)
+       → extend compute_period_matrix() to genus g ≥ 2
+       → requires holomorphic differentials from 10a
+10c  Vollständige Uniformisierung
+       → uniformize arbitrary genus-g surface to canonical constant-curvature metric
+       → depends on 10a + 10b
+```
+
+---
+
 ## Recommended reading
 
 ### Primary source — the dissertation this library implements