setCustomIdErrors

Replace what decode throws. One registration covers the whole process. The last call wins. Call this before any interaction is received.

The stale constructor receives the route prefix. The invalid one receives a detail string. Neither carries the interaction. A per-user locale cannot reach either one.

A seedcord bot already calls this at import, swapping both defaults for Notice subclasses that render a card. Call it again with your own to change what the user reads. Return a Notice subclass from each arm. A plain Error would otherwise reach the user as the generic fault card.