feat(engine): T-1131 browse data proxy — six entity kinds, index+detail, one wire envelope (D-254 SS4)

browse_reader.rs: BrowseReader on the CityContextReader::open() pattern
— six index + six detail reads against systems.db (bodies filterable by
containing system; system/corporation/commodity details fold their join
partners). browse_proxy.rs: BrowseRequest{browse, kind, query} /
BrowseResponse{kind, status, index, detail} wire types + dispatcher;
BrowseIndexRow{id, primary, secondary} generic across kinds;
BrowseDetail a per-kind enum of field-exhaustive structs.

Demux: Inbound::BrowseRequest is the FIFTH map shape — deliberately the
last; the doc's four-shape ceiling is re-pinned at five with rationale
(six kinds x two forms folded into ONE envelope whose internal enums
pick sub-behavior, the AtlasLayerRequest.up_to precedent, instead of
twelve top-level shapes) and a hard rule that a sixth shape must
migrate to the D-225 tagged-envelope framing. Served for BOTH roles,
connection-tagged 1:1 in-order like atlas/starmap/citynames.
serve_browse_requests pub so integration tests drive the true
end-to-end pipeline. Wire-only per D-254 (T-949 precedent); v1
exclusions (cascade geometry, event logs) respected.

30 unit tests + 7 bridge_tcp integration tests (six-kind round-trip
over real TCP, reader-can-browse, no crossed responses between two
readers, unknown-id NotFound, empty-table Ready); 2 pre-existing tests
updated for the new receive_bridge_inputs parameter.

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

server/src/atlas/plugin.rs

@@ -19,6 +19,8 @@ use crate::atlas::atlas_data_proxy::{
 use crate::atlas::attractor_matching::CityPlacement;
 use crate::atlas::body_params_reader::BodyParamsReaderResource;
 use crate::atlas::body_world_state::{BodyWorldStateCache, CACHE_CAPACITY};
+use crate::atlas::browse_proxy::handle_browse_request;
+use crate::atlas::browse_reader::BrowseReaderResource;
 use crate::atlas::city_context_reader::{
     context_from_read_set, CityContextReaderResource, CityEconomicReadSet,
 };
@@ -41,8 +43,8 @@ use crate::atlas::trait_swerve::{
     build_swerve_pools, compute_swerve_rates, SwerveDrivers, SwervePools,
 };
 use crate::bridge::{
-    AtlasRequestBuffer, AtlasResponseBuffer, CityNamesRequestBuffer, CityNamesResponseBuffer,
-    StarMapRequestBuffer, StarMapResponseBuffer,
+    AtlasRequestBuffer, AtlasResponseBuffer, BrowseRequestBuffer, BrowseResponseBuffer,
+    CityNamesRequestBuffer, CityNamesResponseBuffer, StarMapRequestBuffer, StarMapResponseBuffer,
 };
 use crate::seed::{SeedChain, SeedDomain};
 use crate::simulation::generator::{
@@ -68,7 +70,8 @@ impl Plugin for GenerationPlugin {
             .add_systems(
                 Update,
                 serve_city_names_requests.in_set(TickPhase::PreInput),
-            );
+            )
+            .add_systems(Update, serve_browse_requests.in_set(TickPhase::PreInput));
     }
 }
 
@@ -170,6 +173,34 @@ fn serve_city_names_requests(
     }
 }
 
+/// 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)`.
+///
+/// `pub` (unlike its atlas/star-map/city-names siblings, which stay private)
+/// so `server/tests/bridge_tcp.rs`'s browse integration tests can drive the
+/// TRUE full pipeline (demux -> receive_bridge_inputs -> BrowseRequestBuffer
+/// -> serve_browse_requests -> BrowseResponseBuffer -> send_browse_responses)
+/// end-to-end via `RunSystemOnce`, rather than bypassing this system the way
+/// `reader_receives_tagged_star_map_response` bypasses `serve_star_map_requests`
+/// (see that test's own doc comment) because it has no way to call it.
+pub fn serve_browse_requests(
+    mut requests: ResMut<BrowseRequestBuffer>,
+    mut responses: ResMut<BrowseResponseBuffer>,
+    browse_reader: Option<Res<BrowseReaderResource>>,
+) {
+    if requests.0.is_empty() {
+        return;
+    }
+    let reader = browse_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_browse_request(&req, reader)));
+    }
+}
+
 /// Drain finished background work each tick and apply it to the cache (D-206).
 ///
 /// Runs in `PreInput` (off the Rayon workers, on the main thread): a cheap