fix(simulation): address PR #26 review comments (13 items)

Warnings fixed:
- Add WalkAway to all_player_action_variants_roundtrip test
- Warn and skip on unresolvable speaker_entity_id (was silent 0)
- Change MonologueState.shown_ids from Vec to HashSet (O(1) lookup)
- Add cross-plugin ordering: trigger_recognition_monologue after
  detect_anomalies (latent determinism bug)
- Add TODO for unreachable Secret trust tier

Suggestions addressed:
- Server-side range check for Talk verb in handle_talk (CLOSE_RANGE)
- Emit IncompleteInteraction before overwriting ActiveDialogue
- Add different_seed_produces_different_replay determinism test
- Replace panic with assert for unknown fixture naming convention
- Fix duplicate "Observe" label: ExamineNpc now uses "Examine NPC"
- Change DialogueCooldownTracker.used from Vec to BTreeMap (D-041)
- Add .after(process_talk_interaction) to process_walk_away ordering
- Collapse dead conditional in main.rs (both branches identical)

468 tests pass, 0 failures.

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

server/tests/serialization.rs

@@ -98,6 +98,7 @@ fn all_player_action_variants_roundtrip() {
         PlayerAction::SetTickRate(TickRate::Half),
         PlayerAction::ToggleStanceUp,
         PlayerAction::ToggleStanceDown,
+        PlayerAction::WalkAway,
     ];
 
     for action in actions {
@@ -159,7 +160,11 @@ fn all_fixtures_deserialize() {
             rmp_serde::from_slice::<u64>(&bytes)
                 .unwrap_or_else(|e| panic!("deserialize boundary raw fixture {}: {}", name, e));
         } else {
-            panic!("unknown fixture naming convention: {}", name);
+            assert!(
+                false,
+                "unknown fixture naming convention: {} — add a deserialization branch for this prefix",
+                name
+            );
         }
         count += 1;
     }
@@ -533,7 +538,7 @@ fn pending_recognition_wire_roundtrip() {
 #[test]
 fn all_verb_kind_variants_roundtrip() {
     let all_verbs = [
-        (VerbKind::ExamineNpc, "Observe"),
+        (VerbKind::ExamineNpc, "Examine NPC"),
         (VerbKind::Talk, "Talk"),
         (VerbKind::Observe, "Observe"),
         (VerbKind::Read, "Read"),