docs: citation audit + correct 8 mis-citations; add Phases 12/13

External reviewer pass over the literature references. Verified entries
against arXiv/DOI/publisher and corrected misattributions that had
propagated across the docs.

Corrected citations (consistent across all docs):
- Bowers-Bowers-Lutz 2026: title was the 2017 paper's
  -> "Rigidity of Koebe Polyhedra and Inversive Distance Circle Packings"
- Liouville theorem: "Springborn 2019" -> Pinkall & Springborn,
  Geom. Dedicata 214 (2021)
- Bobenko-Pinkall-Springborn: "G&T 14 (2010)" -> G&T 19(4) (2015), 2155-2215
- Optimal Cone Singularities: "Crane, Soliman, Ben-Chen, Schroeder"
  -> Soliman, Slepcev, Crane, ACM TOG 37(4)
- Schlaefli formula: "Rivin, Springborn 1999" -> Rivin, Schlenker
- Quasiconformal distortion: "Springborn, Veselov" -> Born, Buecking,
  Springborn (arXiv:1505.01341)
- Period matrices: "Bobenko, Buecking 2009" (was Bobenko-Mercat-Schmies'
  title) -> Bobenko-Mercat-Schmies 2011 + genuine Bobenko-Buecking 2021
- Fabricated entry: "Alexa 2020, DOI 10.1145/3414685.3417840" pointed to
  an unrelated paper (Pixelor) -> Bunge, Herholz, Kazhdan, Botsch 2020
- Stripe Patterns: "Bonneel et al. 2015" -> Knoeppel, Crane, Pinkall,
  Schroeder 2015

Equation-number corrections (verified against the PDFs):
- Glickenstein 2011 "eq. 4.6" -> "§5.2" (no such equation label exists)
- Springborn 2020 "eq. 4.6" -> "§4 variational gradient"
- inversive-distance attribution softened to classical inversive distance

Other:
- DBFEnergy bibliography (separate repo) and convergence half-sentence in
  novelty-statement.md §3.3 (Bobenko-Buecking 2021)
- Status legend (implemented vs planned) at top of references.md
- New Phase 12 (decorated DCE & geometric transition, Chain A, near-term)
  and Phase 13 (canonical tessellations & polyhedral realisation, Chain B
  capstone) in phases.md + research-track.md; 10c scope-boundary note
  clarifying infrastructure vs Lutz-specific algorithms

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

doc/architecture/phase-9a-validation.md

@@ -124,7 +124,7 @@ energy-evaluation cost and the FD-gradient validation pattern.
 
 ### 2.5  Hessian — finite difference for now
 
-Glickenstein 2011 eq. (4.6) gives an analytic Hessian for the inversive-
+Glickenstein 2011 §5.2 gives an analytic Hessian for the inversive-
 distance variational principle, but is more involved than the Springborn
 cot-Laplacian.  For MVP we rely on FD; the analytic form is a future
 optimisation (joining the Phase 9b roadmap for HyperIdeal as a sibling
@@ -173,7 +173,7 @@ same Newton-time-zero gradient".
 | Angles                     | half-tangent law of cosines                   | (face-internal angles via `p(θ*, Δρ)`)       | half-tangent law of cosines (reuses `euclidean_angles`)            |
 | Gradient                   | `Θ_v − Σ α_v(f)`                              | `φ_f − Σ_{h:face(h)=f} (p+θ*)`               | `Θ_v − Σ α_v(f)`                                                   |
 | Energy form                | path integral (10-pt GL)                      | closed form via `½ p Δρ + Λ(θ*+p) − θ* ρ`   | path integral (10-pt GL)                                           |
-| Hessian                    | analytic (cotangent Laplacian)                | analytic (`sin θ / (cosh Δρ − cos θ)`)       | finite difference (analytic deferred — Glickenstein 2011 eq. 4.6)  |
+| Hessian                    | analytic (cotangent Laplacian)                | analytic (`sin θ / (cosh Δρ − cos θ)`)       | finite difference (analytic deferred — Glickenstein 2011 §5.2)     |
 | Convexity                  | strictly convex after gauge fix               | strictly convex after gauge fix              | locally convex on triangle-inequality domain (Luo 2004 Thm 1.2)    |
 | Gauge fix                  | pin one vertex (`v_idx = −1`)                 | pin one face   (`f_idx = −1`)                | pin one vertex (`v_idx = −1`)                                      |
 
@@ -213,8 +213,9 @@ form.  It does share the Clausen function via `clausen2()` from `clausen.hpp`.
 
 ## 6.  References
 
-- Bobenko, A. I., Pinkall, U. & Springborn, B. (2010). *Discrete conformal
-  maps and ideal hyperbolic polyhedra.* Geometry & Topology 14, 379–426.
+- Bobenko, A. I., Pinkall, U. & Springborn, B. *Discrete conformal
+  maps and ideal hyperbolic polyhedra.* Geometry & Topology 19(4) (2015),
+  2155–2215. arXiv:1005.2698.
 - Bowers, P. L. & Stephenson, K. (2004). *Uniformizing dessins and Belyĭ
   maps via circle packing.* Memoirs of the AMS 170(805).
 - Glickenstein, D. (2011). *Discrete conformal variations and scalar