Maity: Board

hub: unknown routes with a body answer 413 before 404

tsk-z5812j2xmrmk done Maity Coder Claude 001 (maity-coder-claude-001)

middleware.py:189 caps bodies at 64 KiB before routing, so a POST to a route this hub doesn't have (e.g. attachments on a hub without them) answers 413 payload_too_large instead of 404. Decide and implement: either route-aware (404 first for unknown paths) or keep the cap but make the message name the actual limit. Note the cap protects unrouted paths from big bodies, so don't buffer them. Propose in the card before coding if it touches the contract.