feat(bridge): add rng_seed to ObserverSnapshot for deterministic replay (#527)

Adds rng_seed: Option<u64> to ObserverSnapshot. The WRONG button (#507) captures
inputs.jsonl and seed.txt for replay, but seed.txt was writing "unavailable"
because the server did not include the RNG seed in ObserverSnapshot.

Changes:
- bridge/types.rs: PROTOCOL_VERSION 9→10, rng_seed field with serde(default,
  skip_serializing_if = "Option::is_none") for backward compatibility
- perception/observer/mod.rs: inject Res<SimRng> into compute_observer_snapshot,
  populate rng_seed: Some(rng.seed()) each tick
- All test files: add rng_seed: None to ObserverSnapshot constructors
- tests/serialization.rs: bump protocol_version_constant assertion 9→10
- Regenerate msgpack fixtures and golden file for protocol v10

Completes the WRONG button capture loop: replays can now fully reproduce
observed bugs with the exact RNG seed from the capture.

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

server/src/perception/observer/mod.rs

@@ -52,7 +52,7 @@ pub fn compute_visibility_geometry(
 ///
 /// System ordering: after compute_visibility_geometry + compute_nearby_interactions,
 /// before advance_tick.
-#[allow(clippy::type_complexity)]
+#[allow(clippy::type_complexity, clippy::too_many_arguments)]
 pub fn compute_observer_snapshot(
     time: Res<SimulationTime>,
     geometry: Res<VisibilityGeometry>,

server/tests/bridge_ipc.rs

@@ -61,6 +61,7 @@ fn snapshot_roundtrip_over_unix_socket() {
             dialogue_response: None,
             blocked_entities: vec![],
             scan_events: vec![],
+            rng_seed: None,
         };
 
         bridge

server/tests/bridge_tcp.rs

@@ -47,6 +47,7 @@ fn snapshot_roundtrip_over_tcp() {
             dialogue_response: None,
             blocked_entities: vec![],
             scan_events: vec![],
+            rng_seed: None,
         };
 
         bridge

server/tests/gen_fixtures.rs

@@ -37,6 +37,7 @@ fn fixture_snapshot(tick: u64, entities: Vec<VisibleEntity>) -> ObserverSnapshot
         dialogue_response: None,
         blocked_entities: vec![],
         scan_events: vec![],
+        rng_seed: None,
     }
 }
 
@@ -208,6 +209,7 @@ fn generate_msgpack_fixtures() {
         dialogue_response: None,
         blocked_entities: vec![],
         scan_events: vec![],
+        rng_seed: None,
     };
     write_fixture(
         "snapshot_v2_full",

server/tests/golden/proof_room_tick_10.json

@@ -64,9 +64,10 @@
   "player_facing": "North",
   "player_inventory": [],
   "player_stance": "Sprint",
+  "rng_seed": 42,
   "scan_events": [],
   "tick": 8,
-  "version": 9,
+  "version": 10,
   "visible_tiles": [
     {
       "tile_kind": "Wall",

server/tests/serialization.rs

@@ -26,6 +26,7 @@ fn test_snapshot(tick: u64, entities: Vec<VisibleEntity>) -> ObserverSnapshot {
         dialogue_response: None,
         blocked_entities: vec![],
         scan_events: vec![],
+        rng_seed: None,
     }
 }
 
@@ -254,6 +255,7 @@ fn snapshot_v2_fields_roundtrip() {
         dialogue_response: None,
         blocked_entities: vec![],
         scan_events: vec![],
+        rng_seed: None,
     };
 
     let bytes = rmp_serde::to_vec_named(&snapshot).expect("serialize");
@@ -308,7 +310,7 @@ fn protocol_version_constant_matches_snapshot() {
     let snapshot = test_snapshot(0, vec![]);
     assert_eq!(snapshot.version, PROTOCOL_VERSION);
     assert_eq!(
-        PROTOCOL_VERSION, 9,
+        PROTOCOL_VERSION, 10,
         "bump this assertion when protocol version changes"
     );
 }
@@ -348,6 +350,7 @@ fn all_facing_direction_variants_roundtrip() {
             dialogue_response: None,
             blocked_entities: vec![],
             scan_events: vec![],
+            rng_seed: None,
         };
         let bytes = rmp_serde::to_vec_named(&snapshot).expect("serialize");
         let decoded: ObserverSnapshot = rmp_serde::from_slice(&bytes).expect("deserialize");