CLI: restore terminal state on exit

src/runtime.ts

@@ -1,4 +1,5 @@
 import { clearActiveProgressLine } from "./terminal/progress-line.js";
+import { restoreTerminalState } from "./terminal/restore.js";
 
 export type RuntimeEnv = {
   log: typeof console.log;
@@ -16,6 +17,7 @@ export const defaultRuntime: RuntimeEnv = {
     console.error(...args);
   },
   exit: (code) => {
+    restoreTerminalState("runtime exit");
     process.exit(code);
     throw new Error("unreachable"); // satisfies tests when mocked
   },