update proto, add config update publish broadcast, add messages compacting

inc/proto/msg.h

@@ -16,6 +16,7 @@ typedef struct {
     ws_cli_conn_t clientIdx;
     uint8_t*      msg;
     size_t        msgLen;
+    uint64_t      dispatch_us; // microsecond timestamp when queued (for batching window)
 } OutgoingMessage;
 
 // Build a ServerMessage{AuthResponse} frame.  Returns a malloc'd buffer;
@@ -59,12 +60,21 @@ uint8_t* fb_build_stream_reg_confirm(
 
 // Build a ServerMessage{CtrlServerMessage{ConfigNotifMessage{DeviceIdMappingNotif}}} frame.
 // paths: array of NULL-terminated string arrays; path_lens: component count per path.
+// seg_names[i]: array of seg_counts[i] segment name strings for device i.
 uint8_t* fb_build_config_device_id_mapping(
     uint64_t nonce,
     char** paths[], size_t path_lens[],
+    char* seg_names[][64], size_t seg_counts[],
     size_t device_count, size_t* len_out);
 
 // Build a ServerMessage{CtrlServerMessage{ConfigNotifMessage{ConfigLoadError}}} frame.
 uint8_t* fb_build_config_error(uint64_t nonce, const char* message, size_t* len_out);
 
+// Build a ServerMessage{CompactedMessage{frames=[...]}} frame.
+// msgs / msg_lens: array of `count` pre-built ServerMessage byte buffers to pack.
+// The caller retains ownership of the source buffers; this function copies their bytes.
+// Nonce is set to UINT64_MAX (no-nonce / fire-and-forget).
+uint8_t* fb_build_compacted_message(
+    uint8_t* const* msgs, const size_t* msg_lens, size_t count, size_t* len_out);
+
 #endif // __PROTO_MSG_H__