nix templates: factor harness-base.nix (shared scaffolding incl. gitconfig)

hive-c0re/src/lifecycle.rs

@@ -75,7 +75,11 @@ pub fn is_manager(name: &str) -> bool {
 /// extends. Manager → `manager`; everyone else → `agent-base`.
 #[must_use]
 pub fn flake_base(name: &str) -> &'static str {
-    if is_manager(name) { "manager" } else { "agent-base" }
+    if is_manager(name) {
+        "manager"
+    } else {
+        "agent-base"
+    }
 }
 
 fn validate(name: &str) -> Result<()> {