Fix profile picture uploads from the app

Expo's fetch rejects React Native's { uri, name, type } FormData parts ("Unsupported FormDataPart
implementation"), so every upload failed. Upload an expo-file-system File instead, shrunk to 1024 px
first. The server also takes bigger photos (25 MB, sharp's default pixel limit) and logs why a
picture couldn't be read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011Y2iUsKEWDuRGjK5FPmcUP

apps/api/src/routes/avatars.ts

@@ -14,9 +14,11 @@ export async function avatarRoutes(app: FastifyInstance) {
     const file = await req.file({ limits: { fileSize: AVATAR_MAX_UPLOAD_BYTES, files: 1 } }).catch(() => undefined);
     if (!file) throw new HttpError(400, 'Choose a picture to upload');
     const input = await file.toBuffer().catch(() => {
-      throw new HttpError(413, 'That picture is too big (10 MB max)');
+      throw new HttpError(413, `That picture is too big (${AVATAR_MAX_UPLOAD_BYTES / 1024 / 1024} MB max)`);
     });
-    const image = await processAvatar(input);
+    const image = await processAvatar(input, (err) =>
+      req.log.warn({ err, bytes: input.length, mimetype: file.mimetype, filename: file.filename }, 'avatar not readable'),
+    );
 
     const values = { image, contentType: 'image/webp', updatedAt: new Date() };
     await db