chore(simulation): address review suggestions — comments and minor fixes

- monologue.rs: tracing::warn on unrecognized trigger in fallback arm
- disclosure.rs: borrow-sequencing comment, first() simplification note
- trait_modifiers.rs: delegate parse_confidence to KnowledgeConfidence::try_from
- npc_knowledge_transfer.rs: fix misleading "draw randomly" comment,
  document one-directional transfer behavior
- graph.rs: document intentional no-retrigger after contradiction
- dialogue.rs: explain entity grant guardrail asymmetry (D-079)
- knowledge/mod.rs: document one-tick monologue lag from system ordering
- poi_discovery.rs: document D-079 carve-out for direct KG write

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

server/src/simulation/poi_discovery.rs

@@ -81,6 +81,11 @@ pub fn discover_pois(
         }
 
         if can_discover(observer_pos, &geometry, &kg, poi) {
+            // Direct KG write — bypasses the KnowledgeGranted event queue.
+            // Justified for LOS-based physical discovery: the observer sees
+            // the POI directly, no intermediary grant source. This is a D-079
+            // carve-out; NPC tips and research-based POI discovery (Sprint 18)
+            // will use the event queue path.
             kg.facts.insert(
                 fact_id,
                 FactKnowledge {