Dicebear SVG API (minimal, custom)

Usage:
  GET /avataaars.svg?q=<base64url-encoded-json>

Example:
  /avataaars.svg?q=eyJzZWVkIjoiSm9obiIsImJhY2tncm91bmRDb2xvciI6WyJiNmUzZjQiXX0

Notes:
- `q` must be a base64url-encoded JSON string.
- In a browser / UI, use:
    const json = { seed: 'John', backgroundColor: ['b6e3f4'] };
    const jsonStr = JSON.stringify(json);
    const b64 = btoa(jsonStr).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, '');
    const url = `/avataaars.svg?q=${b64}`;
- Only the raw SVG is returned for *.svg endpoints.