feat(simulation): ban HashMap via clippy disallowed_types, fix violations (#343)

Adds server/.clippy.toml with disallowed-types for std::collections::HashMap
and std::collections::HashSet. HashMap iteration order is non-deterministic
and breaks deterministic simulation replay (D-030).

Changes:
- server/.clippy.toml: disallow HashMap and HashSet crate-wide
- simulation/movement.rs: WalkabilityMap.chunks and occupied map → BTreeMap;
  add PartialOrd+Ord to ChunkCoord, TilePosition, TilePresence
- simulation/monologue.rs: MonologueState.shown_ids → BTreeSet (simulation state)
- perception/shadowcast.rs: #![allow] — per-frame FOV scratch, iteration irrelevant
- perception/interpretation.rs: #![allow] — per-frame lookup table, key-only access
- perception/query.rs: #![allow] — sector_lookup is a per-frame read-only cache

Also applies cargo fmt to pre-existing format drift in contraband.rs,
dialogue.rs, test_world/mod.rs, and several integration tests.

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

server/src/perception/interpretation.rs

@@ -3,6 +3,10 @@
 //! Interprets what the observer sees (and doesn't see) against known NPC
 //! routines and knowledge graph state. Produces high-level observation events
 //! that drive monologue and investigation triggers.
+//!
+//! Note: HashSet is used as a per-frame lookup table (visible tiles/NPCs).
+//! Only membership checks — iteration order is irrelevant. Not simulation state.
+#![allow(clippy::disallowed_types)]
 
 use bevy_ecs::prelude::*;
 

server/src/perception/shadowcast.rs

@@ -9,6 +9,12 @@
 //! References:
 //! - Symmetric: https://www.albertford.com/shadowcasting/
 //! - Traditional: RogueBasin recursive shadowcasting
+//!
+//! Note: HashSet is used here as a per-frame scratch accumulator for visible
+//! tile positions during the FOV sweep. Only `insert` and `contains` are used;
+//! iteration order never affects the output (results are handed to BTreeSet in
+//! query.rs). Not simulation state — exempt from the determinism constraint.
+#![allow(clippy::disallowed_types)]
 
 use std::collections::HashSet;