feat: Fibonacci spiral canvas + graph filter + domain sub-hubs

- Wiki Map.canvas: 13 nodes at golden angle 137.5deg (Fibonacci/sunflower pattern)
  - index at center, 3 domain _indexes in ring 1, content in outer rings
  - Color coded: orange=concepts, purple=entities, green=sources, blue=navigation
  - 17 semantic edges with labels
- graph.json: search:path:wiki — eliminates all plugin file noise
  - hideUnresolved:true — removes phantom Subject A/B nodes
  - nodeSizeMultiplier 1.8 — hub nodes visually dominant
  - repelStrength 30 — clean radial spreading
- Created wiki/concepts/_index.md, wiki/entities/_index.md, wiki/sources/_index.md
  - These are domain hub nodes that create the 3-ring hierarchy in graph view
- All wiki pages now link to their domain _index
  - Creates proper hub-and-spoke topology in force-directed graph

wiki/entities/Andrej Karpathy.md

@@ -15,6 +15,7 @@ related:
   - "[[LLM Wiki Pattern]]"
   - "[[Compounding Knowledge]]"
   - "[[Nate Herk LLM Wiki Transcript]]"
+  - "[[entities/_index]]"
 sources:
   - "[[wiki/sources/Nate Herk LLM Wiki Transcript]]"
 ---

wiki/entities/_index.md

@@ -0,0 +1,41 @@
+---
+type: meta
+title: "Entities Index"
+updated: 2026-04-07
+tags:
+  - meta
+  - index
+  - entity
+status: evergreen
+related:
+  - "[[index]]"
+  - "[[Andrej Karpathy]]"
+---
+
+# Entities Index
+
+Navigation: [[index]] | [[concepts/_index|Concepts]] | [[sources/_index|Sources]]
+
+All entity pages — people, organizations, products, and tools.
+
+---
+
+## People
+
+- [[Andrej Karpathy]] — AI researcher, educator; originated the LLM Wiki pattern
+
+---
+
+## Organizations
+
+<!-- Add organization pages here -->
+
+---
+
+## Products & Tools
+
+<!-- Add tool and product pages here -->
+
+---
+
+## Add new entities here as they are identified during ingests.