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/see/settings/ViewSettings.dart

@@ -24,6 +24,14 @@ class ViewSettings extends ParentViewModel {
     );
   }
 
+  /// A new profile photo (or "" to remove it), kept on the device.
+  void savePhoto(String pic) async {
+    final UserDetails details = await getDataManager().getUserDetails();
+    details.pic = pic;
+    await getDataManager().setUserDetails(details);
+    initialise();
+  }
+
   /// The tone slider is capped: it changes register, never cruelty.
   void changeTone(ToneLevel tone) async {
     if (!await hasNetwork(() => changeTone(tone))) return;
@@ -66,8 +74,8 @@ class ViewSettings extends ParentViewModel {
 
       connection.onSickModeChanged(details);
     } catch (e) {
-      handleError(e, () => setSickMode(enabled, reason), () => dismissError(),
-          "Retry");
+      handleError(
+          e, () => setSickMode(enabled, reason), () => dismissError(), "Retry");
     }
   }