feat(ci): ban HashMap in simulation crate via clippy (#343)

Add clippy::disallowed_types for std::collections::HashMap scoped to
the simulation crate. Replace HashMap with BTreeMap in movement.rs for
deterministic iteration order. Allow exception in perception/query.rs
where iteration order is irrelevant (per-frame scratch buffer).

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

server/src/perception/query.rs

@@ -4,6 +4,11 @@
 //! (natural vision, thermal, EM, etc.) implements PerceptionQuery to
 //! provide mode-specific FOV and visibility sector computation.
 //! v0.1 implements only NaturalVision.
+//!
+//! Note: HashMap is used for `sector_lookup` — a per-frame scratch buffer
+//! looked up only by key. Iteration order is irrelevant here. Not subject to
+//! the simulation determinism constraint (see server/.clippy.toml).
+#![allow(clippy::disallowed_types)]
 
 use std::collections::{BTreeSet, HashMap};