fix(election-iomgr-refactor): config replication and RDHUP failover chain

- cluster.c: fix upgradeConfig handler (standbys apply, not primaries)
- cluster.c: fix raw_pkt_copy opcode peek (read scalar before capn_free)
- config_repl.h: enable CONF_ENABLE_UPGRADE_CONFIG=1
- config_repl.c: use client_ssl_ctx for outgoing config fetch connections
- config_repl.c: after config fetch, run cluster_init_phase2 + find_primary
- join.c: push config to newly-joined standbys on OPCode_join
- myapp.c: schedule fetch_config_from_primary after skipping own election
- ha.c: arm heartbeat timeout watchdog after find_and_connect_to_primary

src/controller/myapp.c

@@ -252,6 +252,22 @@ int myapp_run(myconf_t *myconf)
 
 skip_election:;
 
+    /* If we skipped starting our own election (already voted for the winner),
+     * set role to CTRL_STANDBY and trigger config fetch so we can join the cluster. */
+    {
+        ctrl_role_t role = (ctrl_role_t)atomic_load_explicit(&c.ha.role,
+                                                              memory_order_acquire);
+        if (role == CTRL_STANDBY || role == CTRL_INIT) {
+            atomic_store_explicit(&c.ha.role, (int32_t)CTRL_STANDBY,
+                                  memory_order_release);
+            extern int fetch_config_from_primary(cluster_t *c);
+            /* Use delaymgr one-shot so cluster_run is entered before the
+             * blocking fetch starts (fetch runs in delaymgr worker thread). */
+            delay_task_ms(&c.delaymgr, 200, 1,
+                (delay_task_entry_fn_t)fetch_config_from_primary, &c);
+        }
+    }
+
     /* ── Step 9: cluster_run ─────────────────────────────────────────────── */
 
     /* Req 9.4: myapp_run exits into cluster_run within 10ms of startup.