fix(server): address PR #14 review — ordering, docs, version pin

- Fix NpcPlugin system ordering: .before(compute_paths) instead of
  .after(advance_tick) so PathRequests are picked up same frame
- Fix stale doc comment in interpretation.rs: system runs BEFORE
  knowledge events, not after
- Add TODO(v0.2) on RelationshipGraph about information boundary
  limitation for multiplayer
- Document cardinal-only movement as deliberate v0.1 choice
- Add comment on manhattan_distance u32::MAX fallback for cross-z
- Pin pathfinding crate to 4.11

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/Cargo.toml

@@ -11,7 +11,7 @@ rmp-serde = "1"
 bincode = "1"
 rand = "0.9"
 rand_chacha = "0.9"
-pathfinding = "4"
+pathfinding = "4.11"
 thiserror = "2"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }