graph health: fix-categories, cap-degree, link-orphans

Three new tools for structural graph health:

- fix-categories: rule-based recategorization fixing core inflation
  (225 → 26 core nodes). Only identity.md and kent.md stay core;
  everything else reclassified to tech/obs/gen by file prefix rules.

- cap-degree: two-phase degree capping. First prunes weakest Auto
  edges, then prunes Link edges to high-degree targets (they have
  alternative paths). Brought max degree from 919 → 50.

- link-orphans: connects degree-0/1 nodes to most textually similar
  connected nodes via cosine similarity. Linked 614 orphans.

Also: community detection now filters edges below strength 0.3,
preventing weak auto-links from merging unrelated communities.

Pipeline updated: consolidate-full now runs link-orphans + cap-degree
instead of triangle-close (which was counterproductive — densified
hub neighborhoods instead of building bridges).

Net effect: Gini 0.754 → 0.546, max degree 919 → 50.

src/graph.rs

@@ -421,6 +421,11 @@ fn label_propagation(
     adj: &HashMap<String, Vec<Edge>>,
     max_iterations: u32,
 ) -> HashMap<String, u32> {
+    // Only consider edges above this strength for community votes.
+    // Weak auto-links from triangle closure (0.15-0.35) bridge
+    // unrelated clusters — filtering them lets natural communities emerge.
+    let min_strength: f32 = 0.3;
+
     // Initialize: each node gets its own label
     let key_vec: Vec<String> = keys.iter().cloned().collect();
     let mut labels: HashMap<String, u32> = key_vec.iter()
@@ -438,9 +443,10 @@ fn label_propagation(
             };
             if edges.is_empty() { continue; }
 
-            // Count weighted votes for each label
+            // Count weighted votes for each label (skip weak edges)
             let mut votes: HashMap<u32, f32> = HashMap::new();
             for edge in edges {
+                if edge.strength < min_strength { continue; }
                 if let Some(&label) = labels.get(&edge.target) {
                     *votes.entry(label).or_default() += edge.strength;
                 }