feat(raft-apply-decoupling): post-replay apply-correctness verification (task 5.1)

Add apply_verdict_t (APPLY_CLEAN/APPLY_DIVERGENT) computed alongside
the existing structural (CRC) recover_verdict_t. Dual-check design:
an entity-count check (WAL_JOB_SUBMIT entries scanned vs live jobmgr
growth, genuinely independent of apply_committed_entry()'s return
code) and a position check against a new last_applied_lsn field
(forward-looking infrastructure for task 6's live pump).

Fixes a real bug found during review: the position check's
expectation was computed from the physical WAL-scan tip
(current_lsn - 1), which advances past checkpoint markers and
unknown entry types that never reach apply_committed_entry(). A
crash between persist_checkpoint()'s marker-fsync step and its
later snapshot-persist step leaves a trailing checkpoint marker on
next boot, which falsely reported APPLY_DIVERGENT on a perfectly
clean recovery -- reachable today, not gated behind a future task.
Fixed by reading last_applied_lsn directly, which only advances for
entries actually dispatched through the apply seam.

Known accepted gap: entity-count check covers jobs only, not
workers (which can genuinely be created via WAL_WORKER_CTRL) --
documented for future extension.

src/controller/meson.build

@@ -161,6 +161,7 @@ controller_unit_test_src = [
   'testsuite/test_apply_committed_entry.c',
   'testsuite/test_replay_apply_seam.c',
   'testsuite/test_apply_reapply_idempotency.c',
+  'testsuite/test_apply_correctness_verification.c',
   'ctrlstatus.c',
   'commit.c',
   'job.c',