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/DashedOutline.dart

@@ -19,16 +19,15 @@ class DashedOutline extends CustomPainter {
       ..strokeWidth = 1.2;
 
     final Path outline = Path()
-      ..addRRect(RRect.fromRectAndRadius(
-          Offset.zero & size, Radius.circular(radius)));
+      ..addRRect(
+          RRect.fromRectAndRadius(Offset.zero & size, Radius.circular(radius)));
 
     const double dash = 4;
     const double gap = 3;
     for (final metric in outline.computeMetrics()) {
       double distance = 0;
       while (distance < metric.length) {
-        canvas.drawPath(
-            metric.extractPath(distance, distance + dash), paint);
+        canvas.drawPath(metric.extractPath(distance, distance + dash), paint);
         distance = distance + dash + gap;
       }
     }