feat: update .gitignore and enhance ExifPanel styling

- Added .project.json to .gitignore to exclude project identity files.
- Updated ExifPanel styling to include backdrop blur effect for mobile view, improving visual consistency.

Signed-off-by: Innei <tukon479@gmail.com>

.specstory/.gitignore

@@ -1,2 +1,4 @@
 # SpecStory explanation file
 /.what-is-this.md
+# SpecStory project identity file
+/.project.json

apps/web/src/components/ui/photo-viewer/ExifPanel.tsx

@@ -43,9 +43,9 @@ export const ExifPanel: FC<{
     <m.div
       className={`${
         isMobile
-          ? 'exif-panel-mobile fixed right-0 bottom-0 left-0 max-h-[60vh] w-full rounded-t-2xl'
+          ? 'exif-panel-mobile fixed right-0 bottom-0 left-0 max-h-[60vh] w-full rounded-t-2xl backdrop-blur-[70px]'
           : 'w-80 shrink-0'
-      } bg-material-medium z-10 flex flex-col text-white backdrop-blur-[70px]`}
+      } bg-material-medium z-10 flex flex-col text-white`}
       initial={{
         opacity: 0,
         ...(isMobile ? { y: 100 } : { x: 100 }),