Wrap Consensus in a CRITICAL tracer

Although this sounds interesting, I think it might be somewhat difficult to achieve. We would have to trace a tracer everywhere to log these errors as critical, or have some kind of mutable global reference that we consult on critical errors.

I think it would be easier to wrap the Consensus function with a handler of exceptions that captures `ErrorCall` and prints it in a CRITICAL trace.

_Originally posted by @jasagredo in https://github.com/IntersectMBO/ouroboros-consensus/pull/1814#discussion_r2681847648_

Start by locating the Consensus function and the existing tracer handling for ErrorCall and CRITICAL messages. Determine how exceptions are currently captured and where the wrapper belongs; done means ErrorCall failures from Consensus are emitted through a CRITICAL trace without requiring tracing changes everywhere.

Written by the indexing model from the issue text.