[feat] add robust progress management utilities and new tests

tests/progress_manager.rs

@@ -0,0 +1,30 @@
+use polyscribe::progress::ProgressManager;
+
+#[test]
+fn test_total_and_completed_clamp() {
+    let pm = ProgressManager::new_for_tests_multi_hidden(3);
+    pm.set_total(3);
+    pm.inc_completed();
+    pm.inc_completed();
+    pm.inc_completed();
+    // Extra increments should not exceed total
+    pm.inc_completed();
+}
+
+#[test]
+fn test_start_item_does_not_change_total() {
+    let pm = ProgressManager::new_for_tests_multi_hidden(2);
+    pm.set_total(2);
+    let item = pm.start_item("file1");
+    item.set_progress(0.5);
+    // No panic; total bar position should be unaffected. We cannot introspect position without
+    // exposing internals; this test ensures API usability without side effects.
+    item.finish_with("done");
+}
+
+#[test]
+fn test_pause_and_resume_prompt() {
+    let pm = ProgressManager::test_new_multi(1);
+    pm.pause_for_prompt();
+    pm.resume_after_prompt();
+}