feat: Add StageDialogStyler for enhanced dialog management

- Introduced StageDialogStyler class to render child-facing dialogs as shared in-stage cards.
- Preserved native AcceptDialog/ConfirmationDialog signals for stage workflows.
- Implemented methods for applying styles, managing visibility, and handling button actions.
- Added support for dynamic theming and responsive design based on viewport size.
- Created utility functions for styling buttons and managing dialog content.

sandbox_theme.json

@@ -101,9 +101,9 @@
       "queue_size": [680, 520],
       "rule_size": [720, 560],
       "action_size": [560, 390],
-      "confirm_size": [620, 300],
+      "confirm_size": [560, 300],
       "font_size": 22,
-      "message_font_size": 26
+      "message_font_size": 20
     }
   },
   "popups": {
@@ -122,24 +122,31 @@
     },
     "confirmation": {
       "scenery_erase_size": [520, 208],
-      "padding": 18,
-      "body_gap": 10,
+      "padding": 22,
+      "body_gap": 12,
       "footer_gap": 12,
-      "corner_radius": 16,
+      "corner_radius": 18,
       "border_width": 2,
-      "title_font_size": 26,
+      "title_font_size": 28,
       "message_font_size": 20,
       "button_font_size": 20,
-      "button_height": 48,
+      "button_height": 52,
+      "button_min_width": 112,
+      "card_width": 560,
       "button_radius": 12,
       "button_border_width": 2,
       "remove_button_width": 170,
-      "keep_button_width": 132,
+      "keep_button_width": 160,
       "surface_color": "#202633FA",
-      "border_color": "#22C6FF",
-      "accent_color": "#22C6FF",
+      "border_color": "#667386",
+      "secondary_surface": "#293242",
+      "secondary_border": "#718096",
+      "focus_color": "#8BD9FF",
+      "backdrop_color": "#080D15B8",
+      "accent_color": "#8BD9FF",
       "action_color": "#087DBA",
-      "danger_color": "#FF626B",
+      "danger_color": "#E66B75",
+      "danger_surface": "#44262D",
       "danger_hover_surface": "#3B252C",
       "danger_pressed_surface": "#4A252D"
     },