refac: tui: Redesign the action/key bar

- Add: "action" and "disabled action" TUI palette entries.
- Change: Simplify the design of the keys and action names.
- Change: Use plain/default colors, improving the contrast for disabled
  actions.
- Change: Update the "key" and "disabled key" TUI palette entries.

src/termvisage/tui/__init__.py

@@ -202,8 +202,10 @@ def process_input(self, keys):
     ("unfocused box", "", "", "", "#7f7f7f", ""),
     ("focused box", "default"),
     ("green fg", "", "", "", "#00ff00", ""),
-    ("key", "", "", "", "", "#5588ff"),
-    ("disabled key", "", "", "", "#7f7f7f", "#5588ff"),
+    ("key", "reverse"),
+    ("action", "default"),
+    ("disabled key", "", "", "", "#8f8f8f,italics,standout", ""),
+    ("disabled action", "", "", "", "#8f8f8f,italics", ""),
     ("error", "", "", "", "bold", "#ff0000"),
     ("warning", "", "", "", "#ff0000,bold", ""),
     ("notif context", "", "", "", "#0000ff,bold", ""),

src/termvisage/tui/keys.py

@@ -239,9 +239,11 @@ def display_context_keys(context: str) -> None:
     key_bar.set_text(
         [
             [
-                ("key" if enabled else "disabled key", action.replace(" ", "\u2800")),
-                ("key", "\u2800"),
-                ("key" if enabled else "disabled key", f"[{symbol}]"),
+                ("key" if enabled else "disabled key", f"\u2800{symbol}\u2800"),
+                (
+                    "action" if enabled else "disabled action",
+                    "\u2800" + action.replace(" ", "\u2800")
+                ),
                 " ",
             ]
             for action, (_, symbol, _, visible, enabled) in actions