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

.obsidian/graph.json

@@ -1,55 +1,31 @@
 {
   "collapse-filter": false,
-  "search": "",
+  "search": "path:wiki",
   "showTags": false,
   "showAttachments": false,
   "hideUnresolved": true,
   "showOrphans": false,
   "collapse-color-groups": false,
   "colorGroups": [
-    {
-      "query": "path:wiki/entities",
-      "color": { "a": 1, "rgb": 12945088 }
-    },
-    {
-      "query": "path:wiki/concepts",
-      "color": { "a": 1, "rgb": 5227007 }
-    },
-    {
-      "query": "path:wiki/domains",
-      "color": { "a": 1, "rgb": 5227007 }
-    },
-    {
-      "query": "path:wiki/sources",
-      "color": { "a": 1, "rgb": 6986069 }
-    },
-    {
-      "query": "path:wiki/questions",
-      "color": { "a": 1, "rgb": 6986069 }
-    },
-    {
-      "query": "path:wiki/comparisons",
-      "color": { "a": 1, "rgb": 6986069 }
-    },
-    {
-      "query": "path:wiki",
-      "color": { "a": 1, "rgb": 5676246 }
-    },
-    {
-      "query": "path:_templates",
-      "color": { "a": 0.3, "rgb": 6316128 }
-    }
+    { "query": "path:wiki/entities",    "color": { "a": 1, "rgb": 12945088 } },
+    { "query": "path:wiki/concepts",    "color": { "a": 1, "rgb": 5227007  } },
+    { "query": "path:wiki/domains",     "color": { "a": 1, "rgb": 5227007  } },
+    { "query": "path:wiki/sources",     "color": { "a": 1, "rgb": 6986069  } },
+    { "query": "path:wiki/questions",   "color": { "a": 1, "rgb": 6986069  } },
+    { "query": "path:wiki/comparisons", "color": { "a": 1, "rgb": 6986069  } },
+    { "query": "path:wiki/meta",        "color": { "a": 1, "rgb": 5676246  } },
+    { "query": "path:wiki",             "color": { "a": 1, "rgb": 5676246  } }
   ],
   "collapse-display": true,
   "showArrow": true,
   "textFadeMultiplier": -1,
-  "nodeSizeMultiplier": 1.5,
-  "lineSizeMultiplier": 1,
-  "collapse-forces": true,
-  "centerStrength": 0.6,
-  "repelStrength": 25,
-  "linkStrength": 1.2,
-  "linkDistance": 100,
-  "scale": 0.9,
+  "nodeSizeMultiplier": 1.8,
+  "lineSizeMultiplier": 1.2,
+  "collapse-forces": false,
+  "centerStrength": 0.5,
+  "repelStrength": 30,
+  "linkStrength": 1.5,
+  "linkDistance": 120,
+  "scale": 1.0,
   "close": false
 }