The relay now has a generic file upload path that accepts PDFs, random
bytes, and unrecognised formats as application/octet-stream downloads.
SVG with XML declaration is not detected by `infer` and also routes
through the generic path. Updated four content validation tests from
expecting rejection (400/415) to expecting acceptance (200).
Additionally, three WebSocket imeta tests hit /api/events but the
relay route is at /events (no /api prefix). Fixed the URL in all three.
Co-authored-by: Will Pfleger <wpfleger@squareup.com>
Signed-off-by: Will Pfleger <wpfleger@squareup.com>