fix(simulation): PR #176 review round — all 12 findings + 2 recommendations addressed

H1 demux: ShapeProbe defensive multi-shape rejection (union frames now Err, not first-match; +2 tests) and doc claim made honest. H2/T1 SystemIndex.reset_test_state() folded into SimBridge.reset_test_state() (load() inline per autoload rule) + has_pending_request() accessor. H3 no-op tests now assert the replay flag both directions. H4 retry test actually ingests a failure and asserts the retry semantic. H5 error fixture uses the normalized status string. H6 bridge_tcp e2e sends all five frame shapes over real TCP (star-map + city-names buffers asserted). H7 positive replay-on-CONNECTED test via the test_local_bridge test-mode-flip precedent (stub bridge captures + decodes the request bytes). H8/T2 stale PLACEHOLDER doc replaced with the confirmed contract. H9 is_capital doc matches the COALESCE reality. T-r1 demux ceiling written down (next shape = tagged envelope). T-r2 AtlasLayerResponse governance ceiling comment. Lead item: the four cargo-fmt-formatted files from the gate round are now committed (layer_proxy/plugin/bridge-mod/main). H10 note for the record: the 13 snapshot_*.msgpack fixtures in commit 845737617 were regenerated because they were stale against their own generator (pre-existing version-key removal) — verified harmless, no client reads that key.

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

server/src/atlas/attractor_matching.rs

@@ -40,8 +40,9 @@ pub struct CityRecord {
     /// `atlas_city_names.kind == 'capital'` (authored, not derived from
     /// population). Threaded onto [`CityPlacement`] for the Atlas
     /// [`SettlementLayer`](crate::atlas::layer_proxy::SettlementLayer) (T-960 §2).
-    /// Defaults to `false` when the source doesn't track `kind` (e.g. the
-    /// believability harness's own settlement read).
+    /// Every current reader (`city_context_reader` and the believability
+    /// harness's own settlement read) selects `COALESCE(kind,'city')`, so an
+    /// un-authored `kind` yields `false` — there is no kind-less source left.
     pub is_capital: bool,
 }
 

server/src/atlas/layer_proxy.rs

@@ -72,6 +72,11 @@ pub struct DistrictGridLayer {
 /// A layer response: the computed `Layer1Output` + the coarse district grid
 /// (D-225, T-1046) + the road-graph and settlement overlays (T-960 §1/§2), or
 /// a non-ready status.
+///
+/// Growth ceiling (governance-bounded): the one-`Option`-field-per-layer
+/// pattern tops out around six fields — D-226's 2026-07-13 amendment (d)
+/// rules out any L5/tile Atlas layer ever, leaving T-1112 (quarter
+/// footprints) and T-1113 (region climate) as the only remaining candidates.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AtlasLayerResponse {
     pub body_id: String,
@@ -726,8 +731,13 @@ mod tests {
         assert_eq!(decoded.body_id, "GJ1c");
         let rg = decoded.road_graph.expect("road_graph survives round trip");
         assert_eq!(rg.nodes[0].position, (12, 58));
-        assert_eq!(rg.edges[0].maintenance, MaintenanceAuthority::Administrative);
-        let settlements = decoded.settlements.expect("settlements survives round trip");
+        assert_eq!(
+            rg.edges[0].maintenance,
+            MaintenanceAuthority::Administrative
+        );
+        let settlements = decoded
+            .settlements
+            .expect("settlements survives round trip");
         assert_eq!(settlements.settlements[0].name, "Port Aldren");
         assert_eq!(
             settlements.settlements[0].size_class,

server/src/atlas/plugin.rs

@@ -863,10 +863,8 @@ mod tests {
         use std::sync::atomic::{AtomicU32, Ordering};
         static SEQ: AtomicU32 = AtomicU32::new(0);
         let n = SEQ.fetch_add(1, Ordering::Relaxed);
-        let path = std::env::temp_dir().join(format!(
-            "sr_plugin_starmap_{}_{n}.json",
-            std::process::id()
-        ));
+        let path =
+            std::env::temp_dir().join(format!("sr_plugin_starmap_{}_{n}.json", std::process::id()));
         std::fs::write(&path, r#"{"_meta": {}, "nodes": [], "edges": []}"#).unwrap();
 
         let mut world = World::new();