Fix reference Gallery layout: contain-fit, grid-only, no preview hero

The Gallery was cropping uploaded references with object_fit=cover and
blowing up a single image into a hero view that filled the whole panel.
Switch to object_fit=contain (matches gr.Image letterbox behavior),
disable preview / fullscreen / download chrome so uploads stay as
thumbnails in the 4-col grid.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app.py

@@ -163,7 +163,12 @@ with gr.Blocks(title="MegaStyle Style Comparison", theme=gr.themes.Soft()) as de
                 height=360,
                 columns=4,
                 rows=2,
-                object_fit="cover",
+                object_fit="contain",
+                preview=False,
+                allow_preview=False,
+                show_fullscreen_button=False,
+                show_share_button=False,
+                show_download_button=False,
                 interactive=True,
             )