fix: Give all widgets unique IDs in HelpScreen

- Add unique IDs to all Static widgets (spacer_1, spacer_2, spacer_3)
- Fix MountError: 'Tried to insert 3 widgets with same ID'
- Help screen now displays correctly when pressing '?'

src/mail/screens/HelpScreen.py

@@ -38,7 +38,7 @@ class HelpScreen(Screen):
             )
 
             # Custom instructions section
-            yield Static("", id="spacer")
+            yield Static("", id="spacer_1")
             yield Static("[b cyan]Quick Actions[/b cyan]", id="instructions_title")
             yield Static("─" * 70, id="instructions_separator")
             yield Static("")
@@ -58,7 +58,7 @@ class HelpScreen(Screen):
             yield Static("")
 
             # Auto-generated keybindings section
-            yield Static("", id="spacer")
+            yield Static("", id="spacer_2")
             yield Static("[b cyan]Keyboard Shortcuts[/b cyan]", id="bindings_title")
             yield Static("─" * 70, id="bindings_separator")
             yield Static("")
@@ -106,7 +106,7 @@ class HelpScreen(Screen):
             yield Static("")
 
             # Notification compression section
-            yield Static("", id="spacer")
+            yield Static("", id="spacer_3")
             yield Static(
                 "[b cyan]Notification Email Compression[/b cyan]",
                 id="compression_title",