fix: resize w claude code no flicker (#61)

* fix: mouse resize panel failed with claude-code no flicker

* test: run pane mouse reporting drag tests inside tokio runtime

Switch the new horizontal/vertical drag tests to `#[tokio::test]` so
`PaneRuntime::test_with_screen_bytes` has a reactor when it calls
`tokio::spawn`. CI was panicking with "there is no reactor running".

* test: refresh git state in workspace drop slot test

Workspace::test_new caches the parent repo's git branch at construction
time. On master CI the herdr checkout has ref: refs/heads/master in HEAD,
so the cache is populated and workspace_row_height returns 2. On PR CI
actions/checkout uses a detached merge ref, git_branch returns None, row
height becomes 1, and the drop-slot tie-break flips workspace_drop_index_at_row(2)
from Some(0) to Some(1). Refresh git state after pointing identity_cwd at
the per-test temp repo so the cache reflects the temp repo's HEAD.

2 files changed, 155 insertions, 11 deletions

diff --git a/src/app/input/mouse.rs b/src/app/input/mouse.rs
index 0349d236..79237f52 100644
--- a/src/app/input/mouse.rs
+++ b/src/app/input/mouse.rs
@@ -361,10 +361,12 @@ impl AppState {
                     return None;
                 }
 
-                if let Some(info) = self.pane_mouse_target(mouse.column, mouse.row).cloned() {
-                    if self.forward_pane_mouse_button(&info, mouse) {
-                        self.selection = None;
-                        return None;
+                if self.drag.is_none() {
+                    if let Some(info) = self.pane_mouse_target(mouse.column, mouse.row).cloned() {
+                        if self.forward_pane_mouse_button(&info, mouse) {
+                            self.selection = None;
+                            return None;
+                        }
                     }
                 }
 
@@ -489,13 +491,15 @@ impl AppState {
                     return None;
                 }
 
-                if let Some(info) = self.pane_mouse_target(mouse.column, mouse.row).cloned() {
-                    if self.forward_pane_mouse_button(&info, mouse) {
-                        self.selection = None;
-                        self.workspace_press = None;
-                        self.tab_press = None;
-                        self.drag = None;
-                        return None;
+                if self.drag.is_none() {
+                    if let Some(info) = self.pane_mouse_target(mouse.column, mouse.row).cloned() {
+                        if self.forward_pane_mouse_button(&info, mouse) {
+                            self.selection = None;
+                            self.workspace_press = None;
+                            self.tab_press = None;
+                            self.drag = None;
+                            return None;
+                        }
                     }
                 }
 
@@ -1211,6 +1215,144 @@ mod tests {
         assert_ne!(root_layout_ratio(&before), root_layout_ratio(&after));
     }
 
+    #[tokio::test]
+    async fn dragging_vertical_pane_split_still_resizes_when_pane_mouse_reporting_is_enabled() {
+        let mut app = app_for_mouse_test();
+        let mut ws = Workspace::test_new("test");
+        let first_pane = ws.tabs[0].root_pane;
+        let second_pane = ws.test_split(Direction::Vertical);
+
+        app.state.workspaces = vec![ws];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+
+        let pane_infos = app.state.view.pane_infos.clone();
+        let first_info = pane_infos
+            .iter()
+            .find(|info| info.id == first_pane)
+            .expect("first pane info")
+            .clone();
+        let second_info = pane_infos
+            .iter()
+            .find(|info| info.id == second_pane)
+            .expect("second pane info")
+            .clone();
+
+        app.state.workspaces[0].tabs[0].runtimes.insert(
+            first_pane,
+            crate::pane::PaneRuntime::test_with_screen_bytes(
+                first_info.inner_rect.width.max(1),
+                first_info.inner_rect.height.max(1),
+                b"\x1b[?1002h",
+            ),
+        );
+        app.state.workspaces[0].tabs[0].runtimes.insert(
+            second_pane,
+            crate::pane::PaneRuntime::test_with_screen_bytes(
+                second_info.inner_rect.width.max(1),
+                second_info.inner_rect.height.max(1),
+                b"\x1b[?1002h",
+            ),
+        );
+
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+        let border = app
+            .state
+            .view
+            .split_borders
+            .iter()
+            .find(|border| border.direction == Direction::Vertical)
+            .expect("vertical split border")
+            .clone();
+        let before = capture_snapshot(&app.state);
+        let drag_col = border.area.x.saturating_add(1);
+
+        app.handle_mouse(mouse(
+            MouseEventKind::Down(MouseButton::Left),
+            drag_col,
+            border.pos,
+        ));
+        app.handle_mouse(mouse(
+            MouseEventKind::Drag(MouseButton::Left),
+            drag_col,
+            border.pos.saturating_add(4),
+        ));
+
+        let after = capture_snapshot(&app.state);
+        assert_ne!(root_layout_ratio(&before), root_layout_ratio(&after));
+    }
+
+    #[tokio::test]
+    async fn dragging_horizontal_pane_split_still_resizes_when_pane_mouse_reporting_is_enabled() {
+        let mut app = app_for_mouse_test();
+        let mut ws = Workspace::test_new("test");
+        let first_pane = ws.tabs[0].root_pane;
+        let second_pane = ws.test_split(Direction::Horizontal);
+
+        app.state.workspaces = vec![ws];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+
+        let pane_infos = app.state.view.pane_infos.clone();
+        let first_info = pane_infos
+            .iter()
+            .find(|info| info.id == first_pane)
+            .expect("first pane info")
+            .clone();
+        let second_info = pane_infos
+            .iter()
+            .find(|info| info.id == second_pane)
+            .expect("second pane info")
+            .clone();
+
+        app.state.workspaces[0].tabs[0].runtimes.insert(
+            first_pane,
+            crate::pane::PaneRuntime::test_with_screen_bytes(
+                first_info.inner_rect.width.max(1),
+                first_info.inner_rect.height.max(1),
+                b"\x1b[?1002h",
+            ),
+        );
+        app.state.workspaces[0].tabs[0].runtimes.insert(
+            second_pane,
+            crate::pane::PaneRuntime::test_with_screen_bytes(
+                second_info.inner_rect.width.max(1),
+                second_info.inner_rect.height.max(1),
+                b"\x1b[?1002h",
+            ),
+        );
+
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+        let border = app
+            .state
+            .view
+            .split_borders
+            .iter()
+            .find(|border| border.direction == Direction::Horizontal)
+            .expect("horizontal split border")
+            .clone();
+        let before = capture_snapshot(&app.state);
+        let drag_row = border.area.y.saturating_add(1);
+
+        app.handle_mouse(mouse(
+            MouseEventKind::Down(MouseButton::Left),
+            border.pos,
+            drag_row,
+        ));
+        app.handle_mouse(mouse(
+            MouseEventKind::Drag(MouseButton::Left),
+            border.pos.saturating_add(6),
+            drag_row,
+        ));
+
+        let after = capture_snapshot(&app.state);
+        assert_ne!(root_layout_ratio(&before), root_layout_ratio(&after));
+    }
+
     #[test]
     fn wheel_routing_prefers_mouse_reporting() {
         let input_state = crate::pane::InputState {
diff --git a/src/app/input/sidebar.rs b/src/app/input/sidebar.rs
index b806271e..f3ae2b06 100644
--- a/src/app/input/sidebar.rs
+++ b/src/app/input/sidebar.rs
@@ -1121,6 +1121,7 @@ mod tests {
         first.tabs[0]
             .pane_cwds
             .insert(first_root, first_repo.clone());
+        first.refresh_git_ahead_behind();
 
         let mut second = Workspace::test_new("b");
         let second_root = second.tabs[0].root_pane;
@@ -1128,6 +1129,7 @@ mod tests {
         second.tabs[0]
             .pane_cwds
             .insert(second_root, second_repo.clone());
+        second.refresh_git_ahead_behind();
 
         app.state.workspaces = vec![first, second];
         crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));