refactor(examples): group trace examples under examples/system/tracing/

Move 6 trace-related examples (app_trace_basic, app_trace_to_plot,
esp_trace, gcov, sysview_tracing, sysview_tracing_heap_log) from
examples/system/ into a dedicated examples/system/tracing/
subdirectory for better organization.

Update all path references across documentation (en + zh_CN),
build-test-rules, CI configs and component READMEs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KZAGzon27T12sGbDPPbZ8G

examples/system/tracing/app_trace_basic/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(SRCS "app_trace_basic_example_main.c"
+                       PRIV_REQUIRES esp_trace
+                       INCLUDE_DIRS ".")

examples/system/tracing/app_trace_basic/main/app_trace_basic_example_main.c

@@ -0,0 +1,64 @@
+/*
+ * SPDX-FileCopyrightText: 2023-2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+/* Application Trace Basic Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "soc/uart_pins.h"
+#include "esp_log.h"
+#include "esp_app_trace.h"
+
+static const char *TAG = "example";
+
+#if !CONFIG_APPTRACE_DEST_JTAG
+/* Override default uart config to use console pins as a uart channel */
+esp_apptrace_config_t esp_apptrace_get_user_params(void)
+{
+    esp_apptrace_config_t config = APPTRACE_UART_CONFIG_DEFAULT();
+    config.dest_cfg.uart.uart_num = 0;
+    config.dest_cfg.uart.tx_pin_num = U0TXD_GPIO_NUM;
+    config.dest_cfg.uart.rx_pin_num = U0RXD_GPIO_NUM;
+    return config;
+}
+#endif
+
+void app_main(void)
+{
+    if (esp_apptrace_get_destination() == ESP_APPTRACE_DEST_JTAG) {
+        ESP_LOGI(TAG, "Waiting for OpenOCD connection");
+
+        while (!esp_apptrace_host_is_connected()) {
+            vTaskDelay(1);
+        }
+    } else { // UART
+        // Before sending data, wait for the UART host to be ready
+        vTaskDelay(1000 / portTICK_PERIOD_MS);
+    }
+
+    ESP_LOGI(TAG, "Sending example data to the host...");
+
+    for (unsigned int cnt = 1; cnt < 51; ++cnt) {
+        char buf[32] = {0};
+        snprintf(buf, sizeof(buf), "Apptrace test data[%d]:%d\n", cnt, cnt * cnt);
+        esp_err_t res = esp_apptrace_write(buf, strlen(buf), ESP_APPTRACE_TMO_INFINITE);
+        if (res != ESP_OK) {
+            ESP_LOGE(TAG, "Failed to write data to host [0x%x] (%s)", res, esp_err_to_name(res));
+        }
+        esp_apptrace_flush(1000);
+        vTaskDelay(50 / portTICK_PERIOD_MS);
+    }
+
+    ESP_LOGI(TAG, "Done!");
+}