chore(server): auto-format Rust code (cargo fmt)

Pre-existing formatting issues in generator_spike.rs and
validate_ron.rs caught by the new pre-push lint hook.

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

server/src/bin/generator_spike.rs

@@ -1061,7 +1061,9 @@ fn main() {
                     "Unknown zone type: '{}'. Use 'rural' or 'industrial'.",
                     other
                 );
-                eprintln!("(Phase 2 with --from-files supports zone-type IDs like 'rural_agricultural')");
+                eprintln!(
+                    "(Phase 2 with --from-files supports zone-type IDs like 'rural_agricultural')"
+                );
                 process::exit(1);
             }
         };