feat(espnow): add debug logging and channel diagnostics

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/device_test_recv_ch5.py

@@ -0,0 +1,40 @@
+"""Device test: receive ESP-NOW packets on channel 5 (MicroPython)."""
+
+import espnow
+import machine
+import network
+import ubinascii
+import time
+
+
+CHANNEL = 5
+TIMEOUT_MS = 1000
+WDT_TIMEOUT_MS = 10000
+
+
+def _set_channel(channel):
+    sta = network.WLAN(network.STA_IF)
+    sta.active(True)
+    sta.config(pm=network.WLAN.PM_NONE)
+    sta.config(channel=channel)
+
+
+def recv_loop(channel=CHANNEL, timeout_ms=TIMEOUT_MS):
+    wdt = machine.WDT(timeout=WDT_TIMEOUT_MS)
+    _set_channel(channel)
+    e = espnow.ESPNow()
+    e.active(True)
+    print("recv ready ch", channel)
+    while True:
+        wdt.feed()
+        host, msg = e.recv(timeout_ms)
+        if host:
+            mac_hex = ubinascii.hexlify(host).decode()
+            print("rx", mac_hex, "len", len(msg), "hex", ubinascii.hexlify(msg).decode())
+        else:
+            print("rx timeout")
+        time.sleep_ms(10)
+
+
+if __name__ == "__main__":
+    recv_loop()