fix(ha-bootstrap): register listener with iomgr epoll before election

vote_request_thread connects to peers via SSL. iomgr was started before
election but c->ep was only registered with epoll inside cluster_start(),
which runs after election. The TCP connect succeeded (kernel accepts it)
but SSL_accept was never called server-side, so SSL_connect failed
immediately — both vote threads went to deny in <1ms and ctrl-a could
never win a quorum.

Fix: add cluster_register_listener() that wires c->ep into iomgr's
epoll watch. Call it from myapp_run() right after iomgr_start/vtaskmgr_start,
before election. cluster_start() still calls iomgr_monitor again
(idempotent via EPOLL_CTL_MOD).

src/controller/cluster.c

@@ -1095,6 +1095,22 @@ static int check_workers_timeout(void* args)
     return rc;
 }
 
+/*
+ * cluster_register_listener: wire c->ep into iomgr's epoll watch.
+ *
+ * Called before election from myapp_run() so that incoming OP_requestVote
+ * SSL connections are accepted and dispatched during the election phase.
+ * cluster_start() is idempotent — it calls iomgr_monitor again but
+ * iomgr_monitor is safe to call twice (epoll EPOLL_CTL_MOD handles it).
+ */
+int cluster_register_listener(cluster_t *c)
+{
+    endpoint_set_owner(&(c->ep), c);
+    endpoint_set_conn_handler(&(c->ep), (conn_handler_t)handle_connection);
+    c->ep.iomgr = &(c->iomgr);
+    return iomgr_monitor(&(c->ep));
+}
+
 int cluster_start(cluster_t* c)
 {
     int rc;

src/controller/include/cluster.h

@@ -24,6 +24,7 @@ typedef int (*collect_check_fn_t)(void*);
 extern int             check_controller(void*);
 extern int             cluster_init_phase1(cluster_t*);
 extern int             cluster_open_listener(cluster_t*);
+extern int             cluster_register_listener(cluster_t*);
 extern int             cluster_init_phase2(cluster_t*);
 extern int             cluster_init(cluster_t*);
 extern int             cluster_start(cluster_t*);

src/controller/myapp.c

@@ -75,6 +75,19 @@ int myapp_run(myconf_t* myconf)
     iomgr_start(&(c.iomgr));
     vtaskmgr_start(&(c.vtaskmgr));
 
+    /* Register the listener socket with epoll NOW so that iomgr can accept
+     * and dispatch incoming OP_requestVote connections during the election.
+     * Without this, iomgr runs but has no fd to watch — SSL_connect from
+     * peers succeeds at TCP level but hangs waiting for SSL_accept. */
+    {
+        int monitor_rc = cluster_register_listener(&c);
+        if (monitor_rc < 0) {
+            ERROR("cluster_register_listener: %s", strerror(-monitor_rc));
+            cluster_fini(&c);
+            return monitor_rc;
+        }
+    }
+
     /* Pre-load config from disk if a local config file exists, so that this
      * node's config_tag is known before election.  This allows the freshness gate
      * in am_i_primary_quorum() (Req 2.4) to work correctly: a node with a valid