refactor(command): remove key_modifiers from CmdContext

Remove the key_modifiers field from CmdContext struct and all its usages.

This simplifies the command context by removing unused modifier state.
The Cmd trait's execute method no longer receives key modifiers.

Changes:
- Removed KeyModifiers import from cmd.rs
- Removed key_modifiers field from CmdContext struct
- Removed file_path_set field from CmdContext (unused)
- Updated App::cmd_context to not populate key_modifiers
- Removed KeymapSet::registry() accessor
- Updated test code to match new struct layout
- Added documentation to Cmd::name() method

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

src/ui/app.rs

@@ -100,7 +100,7 @@ impl App {
         }
     }
 
-    pub fn cmd_context(&self, key: KeyCode, mods: KeyModifiers) -> CmdContext<'_> {
+    pub fn cmd_context(&self, key: KeyCode, _mods: KeyModifiers) -> CmdContext<'_> {
         let view = self.model.active_view();
         let layout = GridLayout::new(&self.model, view);
         let (sel_row, sel_col) = view.selected;
@@ -113,7 +113,6 @@ impl App {
             search_query: &self.search_query,
             yanked: &self.yanked,
             dirty: self.dirty,
-            file_path_set: self.file_path.is_some(),
             search_mode: self.search_mode,
             formula_panel_open: self.formula_panel_open,
             category_panel_open: self.category_panel_open,
@@ -127,7 +126,6 @@ impl App {
             row_count: layout.row_count(),
             col_count: layout.col_count(),
             key_code: key,
-            key_modifiers: mods,
         }
     }