feat(simulation): #523 add zone_id to ObserverSnapshot (D-077, protocol v11)

Server-tracked zone_id on VisibleTile for D-073 zone crossfade and
D-059 deep fog temperature tint. ZoneMap resource backed by BTreeMap,
observer enrichment in snapshot assembly. Backwards-compatible: v10
payloads deserialize with zone_id: None.

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

server/src/perception/query.rs

@@ -83,6 +83,7 @@ impl PerceptionQuery for NaturalVision {
                     z,
                     visibility: sector,
                     tile_kind,
+                    zone_id: None,
                 }
             })
             .collect();