Problem types

A refusal the API can explain carries one of these in its type. Any other failure is about:blank, and its HTTP status says all there is to say.

• The request is not valid (400)
• Plan limit reached (402)
• Identifier already in use (409)
• Note already exists (409)
• Note deleted (409)
• Snapshot version out of range (409)
• Revision anchor gone (409)
• Device link out of order (409)
• Subscription already active (409)
• Passkey already enrolled (409)
• Note too large (413)
• Storage full (413)
• Inside the bridge cadence (429)
• Ticket invalid (401)
• Feedback allowance used (429)