feat(mdns): Refactor mdns library (stage #1)

The MDNS component has been refactored from a single monolithic file mdns.c
into a set of focused modules with clear responsibilities.
This restructuring maintains the same functionality while improving code organization,
maintainability, and testability.
In the stage#2 we will focus on module based tests
In the stage#3 we will focus on small scale refators and optimizations

components/mdns/private_include/mdns_debug.h

@@ -0,0 +1,65 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <stddef.h>
+#include "sdkconfig.h"
+#include "mdns_private.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef CONFIG_MDNS_ENABLE_DEBUG_PRINTS
+#include "esp_log.h"
+
+/*  Define the debug macros for the mDNS module
+ */
+#define DBG_BROWSE_RESULTS(result, browse) mdns_debug_printf_browse_result(result, browse)
+
+#define DBG_BROWSE_RESULTS_WITH_MSG(result, ...) do { \
+                                                     ESP_LOGD("mdns", __VA_ARGS__);               \
+                                                     mdns_debug_printf_browse_result_all(result); \
+                                                 } while(0)
+
+#define DBG_TX_PACKET(packet, data, len) mdns_debug_tx_packet(packet, data, len)
+
+#define DBG_RX_PACKET(packet, data, len) mdns_debug_rx_packet(packet, data, len)
+
+/**
+ * @brief Print the browse results
+ */
+void mdns_debug_printf_browse_result(mdns_result_t *r_t, mdns_browse_t *b_t);
+
+/**
+ * @brief Print all the browse results
+ */
+void mdns_debug_printf_browse_result_all(mdns_result_t *r_t);
+
+/**
+ * @brief Print the tx packet
+ */
+void mdns_debug_tx_packet(mdns_tx_packet_t *p, uint8_t packet[MDNS_MAX_PACKET_SIZE], uint16_t index);
+
+/**
+ * @brief Print the rx packet
+ */
+void mdns_debug_rx_packet(mdns_rx_packet_t *packet, const uint8_t* data, uint16_t len);
+
+#else
+
+/*  Define the dummy debug macros if debugging is OFF
+ */
+#define DBG_BROWSE_RESULTS(result, browse)
+#define DBG_BROWSE_RESULTS_WITH_MSG(result, ...)
+#define DBG_TX_PACKET(packet, data, len)
+#define DBG_RX_PACKET(packet, data, len)
+
+#endif  // CONFIG_MDNS_ENABLE_DEBUG_PRINTS
+
+#ifdef __cplusplus
+}
+#endif