doc: add visualization links for Bolza and Heawood surfaces

Link to underlying graph drawings (Möbius-Kantor F016A and Heawood F014A)
hosted in the symmetric-graphs repo.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: RaggedR

Archive/BolzaSurface.lean

@@ -13,6 +13,8 @@ GP(8,3). It is a cubic arc-transitive graph on 16 vertices.
   - **Tiling**: {8,3} — 6 octagonal faces on the Bolza surface (genus 2)
   - **CSS code**: [[24, 4, ≥ 6]]
 
+  - [Visualization](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/mobius-kantor-F016A.jpg) — the Möbius-Kantor graph (F016A)
+
 All axioms verified by the Lean kernel (`decide`). No sorry.
 -/
 

Archive/HeawoodSurface.lean

@@ -12,6 +12,8 @@ the Fano plane PG(2,2). It is a cubic arc-transitive graph on 14 vertices.
   - **Tiling**: {6,3} — 7 hexagonal faces on the torus (genus 1)
   - **CSS code**: [[21, 2, ≥ 3]]
 
+  - [Visualization](https://raw.githubusercontent.com/RaggedR/symmetric-graphs/main/lean/named_graphs/heawood-F014A.jpg) — the Heawood graph (F014A)
+
 Vertices 0–6 are the 7 points of the Fano plane.
 Vertices 7–13 are the 7 lines.
 Edge i connects a point to the line containing it.