fix(editor): update message preview bitmap depth to 8-bit indexed format

- Changed the bitmap depth for message previews from 64 to 8 to support indexed palette mode.
- Updated logging to reflect the new depth in message preview creation.
- Enhanced Bitmap class with a new method to update surface pixels, ensuring proper pixel data handling in rendering.

Benefits:
- Improves compatibility with indexed palette formats in message rendering.
- Enhances the clarity of logging for bitmap creation processes.

src/zelda3/screen/title_screen.cc

@@ -279,6 +279,9 @@ absl::Status TitleScreen::RenderBG1Layer() {
       }
     }
   }
+  
+  // Update surface with rendered pixel data
+  tiles_bg1_bitmap_.UpdateSurfacePixels();
 
   return absl::OkStatus();
 }
@@ -332,6 +335,9 @@ absl::Status TitleScreen::RenderBG2Layer() {
       }
     }
   }
+  
+  // Update surface with rendered pixel data
+  tiles_bg2_bitmap_.UpdateSurfacePixels();
 
   return absl::OkStatus();
 }