fix(simulation): Clippy cleanup and CI enforcement (#635)

Fix all Clippy warnings across the server codebase (2411 insertions, 1341
deletions). Raise type-complexity-threshold to 750 and too-many-arguments
to 12 in .clippy.toml for idiomatic Bevy ECS system signatures. The server
now passes `cargo clippy -- --deny warnings` cleanly.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/simulation/knowledge_grant.rs

@@ -20,10 +20,7 @@ use std::collections::BTreeMap;
 pub enum KnowledgeGrant {
     /// Grant knowledge of a non-entity fact.
     /// Format: fact_id "category.topic", confidence string.
-    Fact {
-        fact_id: String,
-        confidence: String,
-    },
+    Fact { fact_id: String, confidence: String },
     /// Grant knowledge of an entity (creates EntityKnowledge entry in observer's KG).
     /// Required for contradiction detection: testimony must create ToldBy EntityKnowledge
     /// so a subsequent DirectObservation can detect a discrepancy (D-079, D-083).