feat(raft-apply-decoupling): point restart replay at apply_committed_entry seam (task 2.3)

Rewire replay_wal()'s per-entry apply call from apply_wal_entry() to
apply_committed_entry() (task 2.2's shared dispatch seam), so restart
replay and the future live commit-advance pump (task 6.1) both
produce materialized state deterministically from the committed log.
apply_wal_entry() is not retired -- it remains ha.c's live standby
catch-up/replicated-apply dispatch, untouched.

Documents a real hazard: replay now fires AFTER_EVENT hooks for the
full post-checkpoint WAL range on every restart, including entries
already applied+notified in a prior process life. Traced and
confirmed inert today for both hook consumers (scheduler registers
post-boot, apiserver gates notify on a connected endpoint empty at
boot); flagged in tasks.md and in-line at the call site for
re-verification before tasks 4.1/6.1/6.2/6.3 make this path broadly
live.

src/controller/meson.build

@@ -159,6 +159,7 @@ controller_unit_test_src = [
   'testsuite/test_persist_snapshot_entities.c',
   'testsuite/test_apply_seam.c',
   'testsuite/test_apply_committed_entry.c',
+  'testsuite/test_replay_apply_seam.c',
   'ctrlstatus.c',
   'commit.c',
   'job.c',