Production (LOG=n, ASSERT=n, RTT=n, reboot-on-fatal) is now the prj.conf
default; debug.conf is the opt-in bundle. Removed prod.conf and the
logging.conf auto-include; relocated RTT/ASSERT out of the always-on
platform confs so they no longer override the prod defaults.
Add CONFIG_ZEPHCORE_COMPANION_USB so the USB CDC companion transport
compiles independently of logging (default-y on USB-capable companions,
opt-in on ESP32-S3 via esp32s3_usb.conf). Gate all USB sites behind one
ZEPHCORE_USB_STACK macro.
Rework BLE/USB interface arbitration to first-come-first-served: neither
transport evicts a live session. Make active_iface mutation thread-safe
(mutex + atomic claim) across the BLE callback thread and USB workqueue.
Share the ESP32-S3 USB OTG / console DTS via common dtsi includes; enable
uart0 (GPIO43/44) on station_g2 and xiao so the console reroute works.
liquidraver