feat: Add streaming pipe support for async loading in.

crates/pikl-core/src/runtime/menu.rs

@@ -154,6 +154,7 @@ pub struct MenuRunner<M: MutableMenu> {
     generation: u64,
     selection: SelectionState,
     visual_anchor: Option<usize>,
+    streaming: bool,
 }
 
 impl<M: MutableMenu> MenuRunner<M> {
@@ -180,6 +181,7 @@ impl<M: MutableMenu> MenuRunner<M> {
             generation: 0,
             selection: SelectionState::new(),
             visual_anchor: None,
+            streaming: false,
         };
         (runner, action_tx)
     }
@@ -312,6 +314,7 @@ impl<M: MutableMenu> MenuRunner<M> {
             mode: self.mode,
             selection_count: self.selection.count(),
             multi_enabled: self.selection.multi_enabled,
+            streaming: self.streaming,
             columns,
             generation: self.generation,
         }
@@ -557,6 +560,11 @@ impl<M: MutableMenu> MenuRunner<M> {
                 self.apply_action(action)
             }
             Action::CloseMenu => ActionOutcome::Closed,
+            Action::StreamingDone => {
+                debug!("streaming done");
+                self.streaming = false;
+                ActionOutcome::Broadcast
+            }
         }
     }
 
@@ -566,6 +574,11 @@ impl<M: MutableMenu> MenuRunner<M> {
         self.mode = mode;
     }
 
+    /// Mark the menu as actively streaming items from stdin.
+    pub fn set_streaming(&mut self, v: bool) {
+        self.streaming = v;
+    }
+
     /// Run the menu event loop. Consumes actions and
     /// broadcasts events.
     ///
@@ -1824,4 +1837,54 @@ mod tests {
         // City "toronto" (7) vs header "City" (4): width = 7
         assert_eq!(cols[2].width, 7);
     }
+
+    // -- Streaming tests --
+
+    #[test]
+    fn streaming_done_sets_streaming_false() {
+        let (mut m, _tx) = test_menu();
+        m.set_streaming(true);
+        m.run_filter();
+        assert!(m.build_view_state().streaming);
+        let outcome = m.apply_action(Action::StreamingDone);
+        assert!(matches!(outcome, ActionOutcome::Broadcast));
+        assert!(!m.build_view_state().streaming);
+    }
+
+    #[test]
+    fn add_items_on_empty_streaming_menu() {
+        let (mut m, _tx) = MenuRunner::new(JsonMenu::new(vec![], "label".to_string()));
+        m.set_streaming(true);
+        m.run_filter();
+        m.apply_action(Action::Resize { height: 20 });
+
+        assert_eq!(m.menu.total(), 0);
+        assert!(m.build_view_state().streaming);
+
+        m.apply_action(Action::AddItems(vec![
+            Value::String("one".into()),
+            Value::String("two".into()),
+        ]));
+        assert_eq!(m.menu.total(), 2);
+        assert_eq!(m.menu.filtered_count(), 2);
+
+        // Confirm on non-empty streaming menu works
+        let outcome = m.apply_action(Action::Confirm);
+        assert!(matches!(outcome, ActionOutcome::Selected { .. }));
+    }
+
+    #[test]
+    fn confirm_on_empty_streaming_menu_is_noop() {
+        let (mut m, _tx) = MenuRunner::new(JsonMenu::new(vec![], "label".to_string()));
+        m.set_streaming(true);
+        m.run_filter();
+        let outcome = m.apply_action(Action::Confirm);
+        assert!(matches!(outcome, ActionOutcome::NoOp));
+    }
+
+    #[test]
+    fn view_state_streaming_defaults_false() {
+        let mut m = ready_menu();
+        assert!(!m.build_view_state().streaming);
+    }
 }