feat: reuse the docked file tree for diff navigation

src/editor.rs

@@ -1281,6 +1281,9 @@ impl Editor {
     fn handle_diff(&mut self, input: Input) {
         // Escape and Tab always retain their modal close/back/focus semantics.
         if !matches!(input, Input::Escape | Input::Char('\t') | Input::BackTab) {
+            if self.handle_tree_binding(&input) {
+                return;
+            }
             match self.selection_bindings.get(&input) {
                 Some(Binding::Action(Action::Down)) => {
                     self.diff.as_mut().expect("active diff").navigate(true);
@@ -2544,7 +2547,11 @@ impl Editor {
     }
 
     pub fn file_navigation_hint(&self) -> &str {
-        if let Some(picker) = &self.file_picker
+        if let Some(picker) = self
+            .diff
+            .as_ref()
+            .and_then(|diff| diff.files.as_ref())
+            .or(self.file_picker.as_ref())
             && picker.view == FileView::Tree
         {
             if picker.searching {
@@ -2612,10 +2619,12 @@ impl Editor {
     }
 
     fn handle_tree_binding(&mut self, input: &Input) -> bool {
-        let Some(picker) = self
-            .file_picker
-            .as_mut()
-            .filter(|picker| picker.focused && picker.view == FileView::Tree)
+        let picker = if let Some(diff) = &mut self.diff {
+            diff.files.as_mut()
+        } else {
+            self.file_picker.as_mut()
+        };
+        let Some(picker) = picker.filter(|picker| picker.focused && picker.view == FileView::Tree)
         else {
             return false;
         };
@@ -2897,19 +2906,7 @@ impl Editor {
             }
             Input::Ctrl('r') => picker.refresh(),
             Input::Ctrl('t') => picker.toggle_view(),
-            Input::Ctrl('u') => picker.clear_filter(),
-            Input::Backspace if picker.view == FileView::List || picker.searching => {
-                picker.backspace()
-            }
-            Input::Char('i') if picker.view == FileView::Tree && !picker.searching => {
-                picker.start_search()
-            }
-            Input::Char(ch)
-                if !ch.is_control() && (picker.view == FileView::List || picker.searching) =>
-            {
-                picker.query.push(ch);
-                picker.refilter();
-            }
+            _ if picker.handle_filter_input(&input) => {}
             Input::Enter => {
                 let Some(path) = picker.accept() else { return };
                 let source = self.jump_location();