feat(core): integrate ternary-types crate with route module

[SuperInstance]

Summary

Integrates the ternary-types crate (v0.1.0) into pincher-core, providing a full route/graph module built on top of the Ternary enum.

Changes

• Depends on ternary-types — a lightweight Ternary enum with serde support (Positive, Neutral, Negative)
• TernaryGraph — ternary-weighted adjacency-list graph supporting both directed and undirected modes
• Shortest paths — Bellman-Ford with negative cycle detection
• All-pairs shortest paths — Floyd-Warshall (O(V³))
• Community detection — signed label propagation
• Connected components — using only positive (trusted) edges
• Spectral clustering — power iteration on signed Laplacian + k-means
• Signed modularity — quality scoring for community assignments
• RoomGraph — high-level named-room wrapper with routing, next-hop, and matrix methods
• 13 tests covering all algorithms

Usage

use pincher_core::route::{RoomGraph, build_routing_graph};

let mut rg = build_routing_graph(&["lobby", "dev", "staging"]);
rg.add_trusted_route(0, 1);
rg.add_trusted_route(1, 2);
let dist = rg.distances_from(0);
assert_eq!(dist[2], Some(2.0));

Notes

• Uses a path dependency for ternary-types until it's published to crates.io
• After publishing, the path dep can be changed to a registry dep