Refactor: Externalize remaining MenuBar tooltips

- Replaced hardcoded tooltips for the log and about buttons with references
  to the 'tooltips' dictionary passed during MenuBar initialization.
- This further enhances the flexibility and translatability of the MenuBar.

menu_bar.py

@@ -128,7 +128,7 @@ class MenuBar(ttk.Frame):
             command=toggle_log_window,
         )
         self.log_btn.grid(column=2, row=0, sticky="e")
-        Tooltip(self.log_btn, "Show Log", state_var=self.tooltip_state)
+        Tooltip(self.log_btn, self.tooltips["show_log"], state_var=self.tooltip_state)
 
         # --- About Button ---
         self.about_btn = ttk.Button(
@@ -139,7 +139,7 @@ class MenuBar(ttk.Frame):
         )
         self.about_btn.grid(column=3, row=0)
         Tooltip(self.about_btn,
-                self.msg_config.STR["about"], state_var=self.tooltip_state)
+                self.tooltips["about_app"], state_var=self.tooltip_state)
 
         # --- Start background update check ---
         self.update_thread = threading.Thread(