Add Vim mode to Biscuit

Related to #405

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/tomlin7/biscuit/issues/405?shareId=XXXX-XXXX-XXXX-XXXX).

config/settings.toml

@@ -16,3 +16,6 @@ cursor_style="line"
 word_wrap=false
 exclude_dirs=[".git"]
 exclude_types=["__pycache__"]
+
+[vim]
+enabled=false

src/biscuit/api/commands.py

@@ -15,6 +15,9 @@ def __init__(self, *a) -> None:
 
         self.register_command = self.settings.register_command
 
+        # Register the toggle Vim mode command in the command palette
+        self.register_command("toggle_vim_mode", self.base.commands.toggle_vim_mode)
+
     @property
     def commands(self) -> None:
         """Return all registered commands"""

src/biscuit/commands.py

@@ -450,3 +450,7 @@ def view_biscuit_licenses(self, *_) -> None:
     def show_about(self, *_) -> None:
         messagebox.showinfo("Biscuit", str(self.base.system))
         self.base.logger.info(str(self.base.system))
+
+    def toggle_vim_mode(self, *_) -> None:
+        self.base.settings.vim.enabled = not self.base.settings.vim.enabled
+        self.base.update_statusbar()

src/biscuit/editor/misc/welcome.py

@@ -97,6 +97,14 @@ def create_quick_group(self):
             ["Ctrl", "Shift", "X"],
         ).pack(fill=tk.X, expand=True)
 
+        QuickItem(
+            quick,
+            "Toggle Vim Mode",
+            Icons.KEYBOARD,
+            self.base.commands.toggle_vim_mode,
+            ["Ctrl", "Shift", "V"],
+        ).pack(fill=tk.X, expand=True)
+
     def create_recent_group(self):
         Label(
             self.container,

src/biscuit/layout/statusbar/statusbar.py

@@ -154,6 +154,16 @@ def __init__(self, master: Frame, *args, **kwargs) -> None:
 
         self.panel_toggle.show()
 
+        # Add Vim mode indicators
+        self.vim_mode_indicator = self.add_button(
+            text="NORMAL",
+            callback=None,
+            description="Vim mode indicator",
+            side=tk.LEFT,
+            padx=(2, 0),
+        )
+        self.vim_mode_indicator.show()
+
     def add_button(
         self,
         text="",
@@ -342,3 +352,11 @@ def change_language(self, language: str) -> typing.Callable:
         return lambda _: self.base.editorsmanager.active_editor.content.text.highlighter.change_language(
             language
         )
+
+    def update_vim_mode_indicator(self, mode: str) -> None:
+        """Updates the Vim mode indicator on the status bar.
+
+        Args:
+            mode (str): The current Vim mode.
+        """
+        self.vim_mode_indicator.change_text(mode)