Three driver fixes for RX duty cycle, all applied to the existing patch

stolen from Zephyr main:

  1. Issue StopTimerOnPreamble=1 before SetRxDutyCycle so the chip's
     timer is not reset on every preamble detect (per §13.1 of the
     datasheet). Without this, duty cycle effectively never sleeps in
     noisy RF and current draw spikes.
  2. On IRQ_RX_TX_TIMEOUT during duty-cycle RX, re-arm via
     sx126x_restart_rx() instead of falling through to set_sleep().
     The old path silently killed duty cycle after the first preamble
     false-positive.
  3. On recv_duty_cycle(NULL) cancel, wake the radio before issuing
     SetStandby — BUSY stays asserted during the sleep phase and the
     standby command was being dropped.

Also adds a dc_timeout_restarts atomic counter incremented on the Fix 2
path, exposed end-to-end: sx126x_ext.h accessors → LoRaRadioBase vtable
→ SX126xRadio override → CommonCLICallbacks → RepeaterMesh. Query via
`get dc.restarts` on the repeater CLI; cleared by `clear stats`. High
values indicate a noisy environment or a too-loose preamble threshold.

(+increase ESP BT stack because future zephyr pin advance will trip that mine)

zephcore/helpers/CommonCLI.cpp

@@ -507,6 +507,9 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
             snprintf(reply, CLI_REPLY_SIZE, "> %d", (int)_prefs->rx_boost);
         } else if (memcmp(config, "rxduty", 6) == 0) {
             snprintf(reply, CLI_REPLY_SIZE, "> %d", (int)_prefs->rx_duty_cycle);
+        } else if (memcmp(config, "dc.restarts", 11) == 0) {
+            snprintf(reply, CLI_REPLY_SIZE, "> %u",
+                     (uint32_t)_callbacks->getDutyCycleTimeoutRestarts());
         } else {
             snprintf(reply, CLI_REPLY_SIZE, "??: %s", config);
         }