Add health metrics

Author: code-shoily

CHANGELOG.md

@@ -48,6 +48,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **ASCII Art Rendering** (`yog/render/ascii`): New module for rendering grids and mazes as ASCII text, ideal for terminal output and debugging.
 
+- **Network Health Metrics** (`yog/health`): New module for measuring graph structural quality:
+  - `diameter/5` - Maximum distance (worst-case reachability)
+  - `radius/5` - Minimum eccentricity (best central point)
+  - `eccentricity/6` - Maximum distance from a specific node
+  - `assortativity/1` - Degree correlation (homophily vs heterophily)
+  - `average_path_length/6` - Typical separation between nodes
+
 - **Grid Distance Heuristics**: Added `chebyshev_distance` (for 8-way movement) and `octile_distance` (for realistic diagonal costs) to `yog/builder/grid`.
 
 - **F# Comparison**: Added `GLEAM_FSHARP_COMPARISON.md` documenting feature parity, API differences, and migration guidance between the Gleam and F# implementations of Yog.

README.md

@@ -35,6 +35,7 @@ A graph algorithm library for Gleam, providing implementations of classic graph
 - **Graph Visualization**: Mermaid, DOT (Graphviz), and JSON rendering
 - **Minimum Spanning Tree**: Kruskal's and Prim's algorithms with Union-Find and Priority Queues
 - **Minimum Cut**: Stoer-Wagner algorithm for global min-cut
+- **Network Health**: Diameter, radius, eccentricity, assortativity, average path length
 - **Directed Acyclic Graphs (DAG)**: Strictly-validated `Dag(n, e)` wrapper bringing O(V+E) DP routines like `longest_path` (Critical Path), LCA, and transitive structures
 - **Topological Sorting**: Kahn's algorithm with lexicographical variant, alongside guaranteed cycle-free DAG-specific sorts
 - **Strongly Connected Components**: Tarjan's and Kosaraju's algorithms