Show real photos for people instead of scene art

Your avatar is your photo, picked from the device by tapping it on Home or
from a new Profile photo row in Settings, shrunk to 256 px and kept on the
phone (there is no upload endpoint yet). Group members show the photo the
server sends in a new `photo` field, everywhere avatars appear. Without a
photo, an initial on a neutral disc. Mock mode bundles free Unsplash
portraits for the sample people.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KhQh614DMeYoQEH9SoMRUw

frontend/lib/Grounded/designs/text/Text.dart

@@ -55,8 +55,8 @@ Widget markedText(
           TextSpan(
             text: parts[index],
             style: TextStyle(
-              fontFamily: getTextType(
-                  index.isOdd ? TextType.Medium : TextType.Regular),
+              fontFamily:
+                  getTextType(index.isOdd ? TextType.Medium : TextType.Regular),
             ),
           ),
       ],