fix(ha): fix config replication to standbys; add replConfigPush handler

- config_repl.c: add handle_repl_config_push — standby handler for
  OPCode_replConfigPush. Verifies SHA-256, saves blob to disk via
  conf_save_config, reloads via load_primary_config, ACKs primary.
- config_repl.h: declare handle_repl_config_push.
- cluster.c: dispatch OPCode_replConfigPush to handle_repl_config_push;
  populate c->myhost_info.name from myconf->name (ctrl-1/ctrl-2/ctrl-3)
  instead of the static "controller" placeholder.
- ha.c: fix raft_cb_become_leader push_config_to_standbys call to pass
  real config bytes and tag read from disk (was NULL/0 — standbys got
  empty push and never saved config).
- typemap.h: add raw_sha256/raw_bytes/raw_bytes_len fields to
  repl_config_push_req_t (mirrors upgrade_config_req_t pattern).
- request.c: pre-extract List(UInt8) sha256/bytes from OPCode_replConfigPush
  before capn_free() in xce_decode(); free them in xce_free_request().
- helper.c: add all HA/replication opcode names to xce_request_op_name
  so "unknown opcode 30" becomes "replConfigPush" in logs.
- cluster_def.h: add embedded myhost_info field to cluster_t struct.
- ha.h: declare ha_start_primary_heartbeat; remove dead
  ha_find_and_connect_to_primary declaration.

src/controller/config_repl.h

@@ -102,6 +102,12 @@ void create_lost_and_found(cluster_t *c);
  */
 int handle_config_request(cluster_t *c, endpoint_t *ep, xce_request_t *req);
 
+/*
+ * handle_repl_config_push: standby handler for OPCode_replConfigPush.
+ * Verifies SHA-256, saves config blob to disk, and reloads cluster_config.
+ */
+int handle_repl_config_push(cluster_t *c, endpoint_t *ep, xce_request_t *req);
+
 /*
  * push_config_to_standbys: fan-out a new config blob to all connected standby
  * controllers in parallel.  Best-effort — standbys that miss the push will