Fork fix: the SDIO wedge is FIXED (esp-hosted-mcu #167)

Root cause (verified against our exact IDF tree, not the community guess):
the "258" in "sdio_write_task: Failed to send data: 258" is NOT a timeout
(that is 263). 258 = 0x102 = ESP_ERR_INVALID_ARG. On the ESP32-P4, block-
mode CMD53 writes require the SOURCE buffer to be 64-byte (cache-line)
aligned; the IDF sdmmc driver rejects a misaligned source with INVALID_ARG
BEFORE any bus activity. esp_hosts write loop then declares "Unrecoverable
host sdio state" and reboots the whole P4. The audio TX payload is not
64-aligned, so streaming mic audio wedged on the very FIRST frame (which is
exactly what we saw: listening -> instant Failed to send -> reboot).

This also explains why buffer/queue/clock/retry tuning all did nothing: the
write never reached the bus. And why our symptom was instant, not after
~100 writes (the community block-mode-desync theory) — it is the first
misaligned buffer, every time.

Fix: vendored esp_hosted 2.12.11 as an editable local component (overrides
the registry copy) and bounce a misaligned TX payload through one aligned
DMA scratch buffer in hosted_sdio_write_block (port_esp_hosted_host_sdio.c).
TX is serialized by the bus lock so a single static bounce buffer is safe;
freed in hosted_sdio_deinit. Host-only change — no C6 reflash.

VERIFIED ON HARDWARE (autonomous self-test): 40s of continuous mic-audio
upstream streaming — the traffic that previously wedged on the first frame
— ran clean, zero timeouts, zero reboots. A guarded SDIO_TX_SELFTEST harness
is kept (compiled out) for future SDIO stress testing.

Credit: root cause + patch designed via multi-agent investigation; the
precise 258=INVALID_ARG decode (correcting the upstream community timeout
assumption) came from checking our actual esp_err.h.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

firmware/components/esp_hosted/slave/main/example_light_sleep.h

@@ -0,0 +1,40 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __EXAMPLE_LIGHT_SLEEP_H__
+#define __EXAMPLE_LIGHT_SLEEP_H__
+
+#include "esp_err.h"
+
+/**
+ * @brief Initialize automatic light sleep example
+ *
+ * This example demonstrates integration of TWO components:
+ * 1. Host power save monitoring (host_power_save.c)
+ * 2. Slave light sleep control (slave_light_sleep.c)
+ *
+ * The example shows automatic light sleep triggered by host power save events:
+ * - Host enters deep sleep → callbacks invoked → slave enters light sleep
+ * - Host wakes up → callbacks invoked → slave exits light sleep
+ *
+ * Users can customize this for different use cases:
+ * - Use only host_power_save callbacks (for custom actions, logging, etc.)
+ * - Use only slave_light_sleep APIs (manual control based on app logic)
+ * - Use both together (automatic mode - shown in this example)
+ * - Add custom conditions (battery level, idle time, task states, etc.)
+ *
+ * To use independently:
+ * - Disable this example, call host_power_save_init() directly
+ * - Disable this example, call slave_light_sleep_start/stop() directly
+ *
+ * @return
+ *     - ESP_OK: Success (even if light sleep component unavailable)
+ *     - ESP_ERR_*: Critical initialization failed
+ */
+esp_err_t example_light_sleep_init(void);
+
+#endif /* __EXAMPLE_LIGHT_SLEEP_H__ */
+