feat(ha-term-safety): restore controller build + wire vote/AE term wire fields (tasks 1.1, 1.2)

1.1: WalCatchupEntry gains term@4/prevLogIndex@5/prevLogTerm@6 (append-only).
1.2: RequestVote/PreVote gain lastLogTerm@4/lastLogIndex@5; cluster.c vote callers
fixed to the extended library arity (RESTORES xce_controller + controller_unit_test
compile+link, broken by the raft-commit-safety signature extension); ha.c emits the
candidate's last-log tuple on send.

5 minimal stub log/commit callbacks wired into s_real_cbs so raft_init's new
non-NULL requirement is satisfied — tasks 2.x replace them with real bodies; the
logOk freshness gate is inert until the term seam (1.3) + on_get_entry_term (2.2).

Pre-existing test_repl_unit.c wal_catchup -EAGAIN failures + ASAN leaks are an
overlayfs /tmp fsync env artifact (bug-850), not from this task (untouched paths;
append-only schema cannot affect the @3 entries-list decode). Build/baseline
isolation is blocked by a c-capnproto flake-hash drift — see Implementation Notes.

src/controller/testsuite/test_ha_vote_gate.c

@@ -474,7 +474,13 @@ static int pre_vote_dispatch_decide(ha_state_t *ha,
 
     int granted = 0;
     if (freshness_ok && from_idx >= 0)
-        granted = (raft_on_pre_vote_request(&ha->raft, from_idx, cand_term)
+        /* ha-term-safety task 1.2: pass candidate (lastLogTerm, lastLogIndex).
+         * These gate tests do not exercise the logOk freshness path, so the
+         * tuple is (0,0); the library's local last-log term also reads 0 (the
+         * on_get_entry_term stub), so logOk grants and pre-existing gate
+         * behavior is unchanged. */
+        granted = (raft_on_pre_vote_request(&ha->raft, from_idx, cand_term,
+                                            0, 0)
                    == RAFT_GRANT) ? 1 : 0;
 
     /* PreVote NEVER adopts the candidate term: the reply carries the voter's