refactor: update TogglePanelAndFocus to use open/focused flags

Update TogglePanelAndFocus and related components to use open/focused flags.

Changed TogglePanelAndFocus from currently_open to open+focused flags.
Parser accepts optional [open] [focused] arguments.

Interactive mode toggles between open+focus and closed/unfocused.

Keymap updates: F/C/V in panel modes close panels when focused.

Model initialization: Virtual categories _Index/_Dim default to None
axis, regular categories auto-assign Row/Column/Page.

App test context updated with visible_rows/visible_cols.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)

src/view/types.rs

@@ -99,6 +99,12 @@ impl View {
         }
     }
 
+    pub fn on_category_removed(&mut self, cat_name: &str) {
+        self.category_axes.shift_remove(cat_name);
+        self.page_selections.remove(cat_name);
+        self.hidden_items.remove(cat_name);
+    }
+
     pub fn set_axis(&mut self, cat_name: &str, axis: Axis) {
         if let Some(a) = self.category_axes.get_mut(cat_name) {
             *a = axis;