agent links: drop VS16 on config's gear too

argus: same failure shape as the screen icon, and icons.tsx's own
comment already names this exact codepoint as unreliable across
fonts. Bare gear, matching every other gear usage in the tree.

hive-agent/src/web_ui/state.rs

@@ -339,7 +339,7 @@ fn agent_links(label: &str, gui_enabled: bool) -> Vec<AgentLink> {
         });
         links.push(AgentLink {
             url: format!("/agent-configs/{label}"),
-            icon: "⚙️".to_owned(),
+            icon: "⚙".to_owned(),
             label: "config".to_owned(),
             kind: AgentLinkKind::Forge,
         });