feat(election-iomgr-refactor): wire RDHUP failover to ha_start_election_async — task 5.2

src/controller/ha.h

@@ -555,6 +555,22 @@ uint64_t ha_trigger_manual_failover_for_test(ha_state_t *ha);
  * the real connect() path. Returns connected fd on success, -errno on failure.
  */
 extern int (*ha_tcp_connect_hook)(const char *host, int port);
+
+/*
+ * ha_rdhup_election_hook: test-only seam for ha_start_election_async in the
+ * RDHUP failover path.
+ *
+ * When non-NULL, ha_on_primary_ctrl_fd_rdhup() calls this INSTEAD OF the real
+ * ha_start_election_async() so unit tests can verify the RDHUP path triggers
+ * async re-election without requiring a live iomgr/delaymgr.
+ *
+ * The hook receives the same arguments that would be passed to ha_start_election_async.
+ * Requirements: 6.3, 6.5, 9.3.
+ */
+extern void (*ha_rdhup_election_hook)(ha_state_t *ha, cluster_t *c,
+                                      int n_peers, xce_candidate_t **peers,
+                                      uint64_t my_config_tag, uint64_t my_lsn,
+                                      const char *my_name);
 #endif
 
 #endif /* HA_H */