ESP32: pin all tskNO_AFFINITY tasks to core 0 via linker wrap

On dual-core ESP32-S3 (ARDUINO_RUNNING_CORE=1), the Arduino loop and
LoRa processing run exclusively on core 1.  ESP-IDF v4 creates mqtt_task
with tskNO_AFFINITY, meaning FreeRTOS may schedule them on core 1 under
load, preempting the LoRa loop.

ESP-IDF v4 provides no public API to change a task's core affinity after
creation (vTaskCoreAffinitySet is IDF v5+ only), and the esp_mqtt_client
config struct has no task_core_id field.  The precompiled Arduino-ESP32
framework cannot be patched via sdkconfig.

Instead, use the GCC/LD --wrap linker mechanism to intercept every call
to xTaskCreatePinnedToCore.  Any task created with tskNO_AFFINITY is
redirected to core 0.  Tasks that are already explicitly pinned (Wi-Fi
driver, LwIP, httpd, esp_timer, ipc0/ipc1) are passed through unchanged.

We intentionally do not filter by task name.  Pinning all unpinned tasks
makes the approach robust against internal ESP-IDF task name changes and
catches any future tasks that may be added with tskNO_AFFINITY.

Verified task layout after the change:
  loopTask  pri=1  core=1   (Arduino loop / LoRa — unchanged)
  mqtt_task pri=5  core=0   (was tskNO_AFFINITY, now pinned)
  httpd     pri=2  core=0   (core_id set explicitly in WebPanelServer)
  tiT       pri=18 core=0   (LwIP, already pinned by ESP-IDF)
  wifi      pri=23 core=0   (Wi-Fi driver, already pinned)
  esp_timer pri=22 core=0   (already pinned)
  ipc0/ipc1 pri=24 core=0/1 (IPC, already pinned per-core)

The -Wl,--wrap flag and arch/esp32/task_pinning.c are added only to
[esp32_base] (IDF v4).  The ESP32-C6 pioarduino target (IDF v5) is
unaffected and can use vTaskCoreAffinitySet() if needed in the future.

platformio.ini

@@ -64,7 +64,9 @@ extra_scripts =
 build_flags = ${arduino_base.build_flags}
   -D ESP32_PLATFORM
 ;  -D ESP32_CPU_FREQ=80          ; change it to your need
+  -Wl,--wrap=xTaskCreatePinnedToCore
 build_src_filter = ${arduino_base.build_src_filter}
+  +<../arch/esp32/task_pinning.c>
 
 [esp32_ota]
 lib_deps =