Merge colloc_graph into main

Author: atantos

README.md

@@ -203,13 +203,24 @@ tests = comparison.statistical_tests
 
 ### Collocation Networks
 
-Build and export word association networks:
+Build and export word association networks with richer metadata:
 
 ```julia
 network = colloc_graph(
-    corpus, ["climate", "change"],
-    metric=PMI, depth=2, min_score=3.0
+    corpus, ["climate", "change"];  # seed terms
+    metric=PMI,
+    depth=2,
+    min_score=2.5,
+    direction=:undirected,
+    include_frequency=true,
+    weight_normalization=:minmax,
+    compute_centrality=true,
+    centrality_metrics=[:pagerank, :betweenness]
 )
+
+first(network.edges, 5)          # includes Frequency / DocFrequency / NormalizedWeight
+first(network.node_metrics, 5)    # includes degrees, strengths & centrality scores
+
 gephi_graph(network, "nodes.csv", "edges.csv")
 ```
 

data_austen/Emma.txt

@@ -297,18 +297,25 @@ network = colloc_graph(
     min_score=-10.0,
     max_neighbors=5,
     windowsize=5,
-    minfreq=1
+    minfreq=1,
+    direction=:undirected,
+    include_frequency=true,
+    weight_normalization=:zscore,
+    compute_centrality=true
 )
 
 println("\nCollocation Network:")
 println("  Nodes: $(length(network.nodes))")
 println("  Edges: $(nrow(network.edges))")
 
-if !isempty(network.edges)
-    println("\nStrongest connections:")
-    for row in eachrow(first(sort(network.edges, :Weight, rev=true), 5))
-        println("  $(row.Source) → $(row.Target): $(round(row.Weight, digits=2))")
-    end
+println("\nTop weighted connections:")
+for row in eachrow(first(sort(network.edges, :Weight, rev=true), 5))
+    println("  $(row.Source) ↔ $(row.Target): score=$(round(row.Weight, digits=2)), freq=$(row.Frequency)")
+end
+
+println("\nCentrality (Pagerank):")
+for row in eachrow(first(sort(network.node_metrics, :Centrality_pagerank, rev=true), 5))
+    println("  $(row.Node): pagerank=$(round(row.Centrality_pagerank, digits=4))")
 end
 ```
 

data_austen/Mansfield_Park.txt

@@ -220,12 +220,18 @@ network = colloc_graph(
     corpus, ["innovation"],
     metric=LLR,
     depth=1,
-    minfreq=1
+    minfreq=1,
+    include_frequency=true,
+    weight_normalization=:rank,
+    compute_centrality=true
 )
 
-network.node_metrics
+first(network.edges, 5)
 ```
 
+The returned `node_metrics` table now includes degree/strength totals and optional
+centrality scores, providing a quick overview of the structural role of each term.
+
 ### Comparative Analysis
 
 Compare associations across subcorpora: