feat(simulation): add NPC name masking with role labels and color index

Server-side infrastructure for information asymmetry in dialogue.
NPCs display role labels (Worker, Supervisor, Patron) instead of
real names until the player explicitly learns them via KG lookup.
NpcColorIndex (stable_id % 8) persists across name reveal.

ConversationEvent and DialogueResponseEvent carry display names +
color indices on the wire with serde(default) for compat.

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

server/src/main.rs

@@ -131,6 +131,11 @@ fn main() {
     app.add_plugins(BridgePlugin);
     app.add_plugins(settled_reach_server::knowledge::KnowledgePlugin);
     app.add_plugins(settled_reach_server::npc::NpcPlugin);
+    // Content root is at the repo root, one level up from server/
+    app.insert_resource(settled_reach_server::content::ContentConfig {
+        content_root: std::path::PathBuf::from("../content"),
+        hot_reload: false,
+    });
     app.add_plugins(settled_reach_server::content::ContentPlugin);
     app.insert_resource(BridgeResource::new(bridge));