Profile pictures, display name default, coloured service names

- Upload a profile picture on web and mobile. The API square-crops it to
  512px WebP, strips metadata (phone photos carry GPS), stores it in
  Postgres and serves it with immutable caching. Avatar URLs are stored as
  paths, so they survive moving the API. Arbitrary avatar URLs are no
  longer accepted (they'd let a profile track its viewers).
- New accounts get the username as typed as their display name; existing
  accounts are backfilled, and clearing it falls back to the username.
- Service names in Settings get a brand-coloured badge and larger type.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/api/src/routes/avatars.ts

@@ -0,0 +1,56 @@
+import { eq } from 'drizzle-orm';
+import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
+import { db, schema } from '../db';
+import { requireUser } from '../lib/auth';
+import { AVATAR_MAX_UPLOAD_BYTES, processAvatar } from '../lib/avatars';
+import { HttpError } from '../lib/http';
+import { toMeDTO } from './me';
+
+export async function avatarRoutes(app: FastifyInstance) {
+  /** Multipart upload with one file field. Returns the updated profile. */
+  app.post('/me/avatar', { config: { rateLimit: { max: 20, timeWindow: '1 hour' } } }, async (req) => {
+    const user = requireUser(req);
+    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)');
+    });
+    const image = await processAvatar(input);
+
+    const values = { image, contentType: 'image/webp', updatedAt: new Date() };
+    await db
+      .insert(schema.avatars)
+      .values({ userId: user.id, ...values })
+      .onConflictDoUpdate({ target: schema.avatars.userId, set: values });
+    // The version busts caches, since the image itself is served as immutable.
+    const [updated] = await db
+      .update(schema.users)
+      .set({ avatarUrl: `/avatars/${user.id}?v=${values.updatedAt.getTime()}` })
+      .where(eq(schema.users.id, user.id))
+      .returning();
+    return toMeDTO(updated!);
+  });
+
+  app.delete('/me/avatar', async (req) => {
+    const user = requireUser(req);
+    await db.delete(schema.avatars).where(eq(schema.avatars.userId, user.id));
+    const [updated] = await db.update(schema.users).set({ avatarUrl: null }).where(eq(schema.users.id, user.id)).returning();
+    return toMeDTO(updated!);
+  });
+
+  app.get('/avatars/:userId', async (req, reply) => {
+    const { userId } = z.object({ userId: z.uuid() }).parse(req.params);
+    const [row] = await db
+      .select({ image: schema.avatars.image, contentType: schema.avatars.contentType })
+      .from(schema.avatars)
+      .where(eq(schema.avatars.userId, userId));
+    if (!row) throw new HttpError(404, 'No picture');
+    return reply
+      .header('Content-Type', row.contentType)
+      .header('Cache-Control', 'public, max-age=31536000, immutable')
+      .header('Content-Security-Policy', "default-src 'none'")
+      .header('Cross-Origin-Resource-Policy', 'cross-origin')
+      .send(row.image);
+  });
+}