feat(simulation): feature-name pipeline wired + legacy window_granularity u32 retired (T-1169, T-1159)

One commit for two tickets whose changes share the bridge/plugin
plumbing files. T-1169 connects the three dormant feature-name pieces:
atlas_feature_names populated at regen (17,891 rows — 15,190 mountain,
2,701 river — via populate_atlas_feature_names mirroring the city-names
importer; systems.db regenerated, stamp fresh), attach_feature_names
wired into the cascade's Topography block with name pools threaded
DB-free through AnalyzeBody (D-225 pattern) and assignments stored on
Layer1Output/BodyWorldState for future consumers, and a
FeatureNamesRequest/Response read proxy as the bridge's 7th tagged
envelope (D-236 pattern, both SimBridge impls). Client label DRAW is
deliberately NOT here — implementation proved both river and mountain
labels need a wire-carried position (the pool is position-free; course
polylines aren't correlated with the named attractors by construction) —
deferred to T-1195's single design pass. cascade_layer1 golden re-pinned
(additive feature_names field).

T-1159 retires the legacy u32 granularity field fully shadowed by
window_granularity_v2: AtlasLayerRequest.window_granularity,
DistrictWindowLayer.granularity echo, the u32::MAX sentinel, and
resolve_window_granularity are gone server-side; client encode paths and
the caller-less atlas_window_cache legacy key component dropped;
msgpack fixtures regenerated; the T-1150 aliasing regression test now
drives through the surviving enum field. The district_window carrier
itself survives byte-compatible per D-255(c).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/src/atlas/plugin.rs

@@ -15,7 +15,8 @@ use std::collections::BTreeMap;
 use std::sync::Arc;
 
 use crate::atlas::atlas_data_proxy::{
-    handle_city_names_request, handle_star_map_request, StarMapDataPath,
+    handle_city_names_request, handle_feature_names_request, handle_star_map_request,
+    StarMapDataPath,
 };
 use crate::atlas::attractor_matching::CityPlacement;
 use crate::atlas::body_params_reader::BodyParamsReaderResource;
@@ -52,7 +53,8 @@ use crate::atlas::trait_swerve::{
 };
 use crate::bridge::{
     AtlasRequestBuffer, AtlasResponseBuffer, BrowseRequestBuffer, BrowseResponseBuffer,
-    CityNamesRequestBuffer, CityNamesResponseBuffer, StarMapRequestBuffer, StarMapResponseBuffer,
+    CityNamesRequestBuffer, CityNamesResponseBuffer, FeatureNamesRequestBuffer,
+    FeatureNamesResponseBuffer, StarMapRequestBuffer, StarMapResponseBuffer,
     StepCanvasRequestBuffer, StepCanvasResponseBuffer,
 };
 use crate::seed::{SeedChain, SeedDomain};
@@ -83,6 +85,10 @@ impl Plugin for GenerationPlugin {
                 Update,
                 serve_city_names_requests.in_set(TickPhase::PreInput),
             )
+            .add_systems(
+                Update,
+                serve_feature_names_requests.in_set(TickPhase::PreInput),
+            )
             .add_systems(Update, serve_browse_requests.in_set(TickPhase::PreInput))
             .add_systems(
                 Update,
@@ -201,6 +207,26 @@ fn serve_city_names_requests(
     }
 }
 
+/// Drain inbound feature-names requests and serve each through the proxy
+/// (T-1169): D-236 Sol check, then the names-only `atlas_feature_names` read.
+/// Mirrors [`serve_city_names_requests`] exactly.
+fn serve_feature_names_requests(
+    mut requests: ResMut<FeatureNamesRequestBuffer>,
+    mut responses: ResMut<FeatureNamesResponseBuffer>,
+    city_reader: Option<Res<CityContextReaderResource>>,
+) {
+    if requests.0.is_empty() {
+        return;
+    }
+    let reader = city_reader.as_ref().map(|r| &r.0);
+    let pending: Vec<_> = requests.0.drain(..).collect();
+    for (conn_id, req) in pending {
+        responses
+            .0
+            .push((conn_id, handle_feature_names_request(&req, reader)));
+    }
+}
+
 /// Drain inbound data-browser requests and serve each through the proxy
 /// (D-254 §4, T-1131): one of the six v1 registry-tier entity kinds, dispatched
 /// to `BrowseReader` by `(kind, query)`.
@@ -1043,6 +1069,8 @@ mod tests {
                 cities: vec![],
                 dominant_faction: None,
                 body_params: None, // T-1023: no DB params in this unit test
+                river_names: vec![],
+                mountain_names: vec![],
             },
             GenPriority::Immediate,
         );
@@ -1079,7 +1107,6 @@ mod tests {
                 up_to: CascadeLayer::Topography,
                 window_center: None,
                 window_n: 0,
-                window_granularity: 0,
                 window_granularity_v2: None,
                 window_min_wl_m: 0,
             },
@@ -1193,6 +1220,36 @@ mod tests {
         assert!(world.resource::<CityNamesRequestBuffer>().0.is_empty());
     }
 
+    #[test]
+    fn serve_feature_names_without_reader_is_error() {
+        use crate::atlas::atlas_data_proxy::{FeatureNamesRequest, FeatureNamesStatus};
+
+        let mut world = World::new();
+        world.insert_resource(FeatureNamesRequestBuffer(vec![(
+            ConnectionId(0),
+            FeatureNamesRequest {
+                feature_names: true,
+                body_id: "GJ1c".to_string(),
+            },
+        )]));
+        world.insert_resource(FeatureNamesResponseBuffer::default());
+        // No CityContextReaderResource.
+
+        let mut sched = Schedule::default();
+        sched.add_systems(serve_feature_names_requests);
+        sched.run(&mut world);
+
+        let responses = world.resource::<FeatureNamesResponseBuffer>();
+        assert_eq!(responses.0.len(), 1);
+        assert_eq!(responses.0[0].0, ConnectionId(0), "connection id preserved");
+        assert_eq!(responses.0[0].1.body_id, "GJ1c");
+        assert!(matches!(
+            responses.0[0].1.status,
+            FeatureNamesStatus::Error(_)
+        ));
+        assert!(world.resource::<FeatureNamesRequestBuffer>().0.is_empty());
+    }
+
     fn sample_read_set() -> CityEconomicReadSet {
         use crate::simulation::generator::SettlementClass;
         CityEconomicReadSet {