refactor(firmware): remove the retired simulation workflow

Remove the retired simulator workspace member, dependencies, workflow
and documentation. Keep the shared flight and hardware crates.

Validation: retirement prefix host check, command-dispatch tests and
book build.

docs/src/errors.md

@@ -79,7 +79,7 @@ different reportable error is already pending.
   The message kind itself identifies an error; no level is duplicated in the
   payload. Dynamic human-readable context belongs in `LOG`, while
   structured protocol failures remain in their owning response message.
-- Control, navigation, safety, and simulator error types are derive-ready but
+- Control, navigation, and safety error types are derive-ready but
   their live owners are not yet attached to a MAVLink worker.
 
 F722 still uses `panic-halt`; it does not claim a live panic frame or