Injector: protocol client code registration

Context

This MR is the final step in moving the injector outside of proto_alpha. Each protocol specific code must now be registered by a side effect in the injector and the appropriate one is chosen automatically (either to simulate operations in the current head, or to recover statuses of operations).

This MR follows !7685 (merged).

Manually testing the MR

The injector should still work the same for protocol specific rollup nodes.