feat(raft-adapter-conformance): route post-connect vote/PreVote failures to production tally

Splits vote_ep_err_handler into a real-vote handler and a new
pre_vote_ep_err_handler, each registered at its existing (already
separate) connection-setup call site. Extracts the identical
CTRL_PRIMARY-role cleanup into a shared vote_ep_handle_promoted_disconnect
helper, behavior unchanged.

Each handler's election-phase branch now routes a post-connect failure
(RDHUP/SSL-error/remote-close after connect, before any reply) through
the same production tally the connect-time failure branches already
use (vote_reply_dispatch / pre_vote_reply_dispatch, bug-1423/1424's
fix), instead of the legacy handle_request_vote_reply that never
updated the tally. Closes the one failure window bug-1423 didn't cover.

1060 -> 1061 tests, 0 failures. PreVote-specific test coverage is
task 3.2's scope (pre_vote_reply_dispatch has no hook seam analogous
to xce_vote_reply_hook; verified only by code symmetry + full-suite
regression here).

src/controller/testsuite/test_ha_vote_send.c

@@ -654,6 +654,68 @@ static void test_bug1417_middle_index_real_vote_from_peer2_not_dropped(void)
     printf("test_bug1417_middle_index_real_vote_from_peer2_not_dropped: PASS\n");
 }
 
+/* ── raft-adapter-conformance task 3.1: post-connect vote failure routing ──
+ *
+ * vote_ep_err_handler's election-phase branch (the iomgr err_handler fired
+ * when an already-connected outgoing vote endpoint fails/closes before a
+ * reply arrives) must count that outcome through vote_reply_dispatch -- the
+ * SAME production tally path a connect-time failure (raft_cb_send_vote_request's
+ * own rc<0 branches, bug-1423) or a delivered denial (vote_reply_msg_handler)
+ * uses -- not the legacy handle_request_vote_reply, which bypasses
+ * raft_on_vote_reply entirely and, critically for this test, never reaches the
+ * xce_vote_reply_hook seam vote_reply_dispatch checks.
+ *
+ * Test seam: xce_vote_reply_hook (checked ONLY inside vote_reply_dispatch) lets
+ * us observe, without a live iomgr/raft election, whether the post-connect
+ * failure reached the production tally path.  Pre-fix, this hook is never
+ * invoked by vote_ep_err_handler's election branch -- proving the bug.
+ */
+
+extern int vote_ep_err_handler_for_test(endpoint_t *ep);
+
+static void test_post_connect_vote_failure_routes_through_production_tally(void)
+{
+    reset_reply_mock();
+
+    ha_state_t ha;
+    TEST_ASSERT_EQUAL_INT(0, ha_init(&ha, &g_vote_cfg, 0));
+    /* Election phase, not CTRL_PRIMARY -- exercises the "else" branch. */
+    atomic_store_explicit(&ha.role, CTRL_ELECTING, memory_order_release);
+    atomic_store_explicit(&ha.term, 4ULL, memory_order_release);
+
+    ha_elect_ctx_t *ctx = alloc_ctx_for_vote(2);
+    pthread_mutex_init(&ctx->lock, NULL);
+
+    endpoint_t ep;
+    make_endpoint(&ep);
+
+    /* Build a real-vote endpoint context as if raft_cb_send_vote_request had
+     * already connected it (on_vote_connected fired, request sent) -- then
+     * the connection fails before any reply arrives: iomgr invokes the
+     * registered err_handler on this same ep. */
+    vote_ep_ctx_build_for_test(&ep, &ha, ctx, /*peer_idx=*/0,
+                                4ULL, 100ULL, 50ULL, "ctrl-a");
+
+    int rc = vote_ep_err_handler_for_test(&ep);
+    TEST_ASSERT_EQUAL_INT(0, rc);
+
+    TEST_ASSERT_EQUAL_INT_MESSAGE(1, g_reply_hook_calls,
+        "post-connect vote failure must reach vote_reply_dispatch's tally "
+        "(xce_vote_reply_hook), not the legacy handle_request_vote_reply path "
+        "which never invokes this hook");
+    TEST_ASSERT_EQUAL_INT_MESSAGE(0, g_reply_granted,
+        "a post-connect failure must be counted as a denied vote (granted=0)");
+    TEST_ASSERT_EQUAL_UINT64_MESSAGE(4ULL, g_reply_term,
+        "the synthesized denial must carry the candidate's own term");
+    TEST_ASSERT_EQUAL_INT_MESSAGE(0, g_reply_peer_idx,
+        "peer_idx must match the failed endpoint's vote_ep_ctx_t peer_idx");
+
+    free(ep.data);
+    free_ctx_for_vote(ctx);
+    ha_fini(&ha);
+    printf("test_post_connect_vote_failure_routes_through_production_tally: PASS\n");
+}
+
 /* ── Suite entry point ───────────────────────────────────────────────────── */
 
 void test_ha_vote_send(void)
@@ -670,4 +732,6 @@ void test_ha_vote_send(void)
     RUN_TEST(test_vote_reply_handler_no_uaf);
     /* bug-1417 */
     RUN_TEST(test_bug1417_middle_index_real_vote_from_peer2_not_dropped);
+    /* raft-adapter-conformance task 3.1 */
+    RUN_TEST(test_post_connect_vote_failure_routes_through_production_tally);
 }