feat(simulation): knowledge grant schema, events, and contradiction detection (#545, #546, #547)

KnowledgeGrant untagged enum (Fact + Entity variants), ContentEntityRegistry
resource, KnowledgeGranted event processing, ContradictionClaim struct with
600-tick window detection in observe_entity. Wires knowledge_grant field in
dialogue line selection. Implements D-079, D-083. Closes Q-026.

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

server/src/simulation/contraband.rs

@@ -127,6 +127,7 @@ pub fn check_contraband_scan(
                         source: KnowledgeSource::DirectObservation { tick: time.tick },
                         state: KnowledgeState::Active,
                         acquired_tick: time.tick,
+                        disclosure_blocked: false,
                     },
                 );
 
@@ -463,6 +464,7 @@ mod tests {
                 source: KnowledgeSource::DirectObservation { tick: 0 },
                 state: KnowledgeState::Active,
                 acquired_tick: 0,
+                disclosure_blocked: false,
             },
         );