Assembles the st-pvpz, st-1wls, and st-mv7t fragments into a 2.4.0
section and deletes them, and moves the README requirement to ~> 2.4.

ADR-0066's SemVer commitment makes this a minor release. The public
surface only grows: an opt-in `:inherit_invoke_handlers` option on
`Statifier.Session.start_link/2`, and a widened `dispatch_ctx` type on
`Statifier.Invoke.SyncHandler.Adapter.dispatch/4` that admits contexts
the old spec rejected. The interpreter now raising `error.execution`
for an `<invoke>` type absent from a set the caller declared is the one
behavior change, and it breaks only code that relied on a silently
parked run: the effect it replaces was never recorded in
`active_invocations`, so no answer fed back against it could resolve.

Prep only, per campaign-024 ruling R-e: the tag and the Hex publish
stay with the operator.

Refs: st-jysb