Place firmware .bin files at the SD card root or staging directory
(/fs/microsd/ufw_staging/); on boot the UAVCAN server migrates them
to /fs/microsd/ufw/ and updates FW.db, then flashes any connected
node whose firmware version mismatches.
- Add firmware migration from SD root and staging dir into /fs/microsd/ufw/
- Maintain FW.db flat-file database mapping board IDs to original filenames
- Use cache-aligned DMA-safe read/write buffers (required on STM32H7)
- Add Tools/auterion/remote_update_fmu.sh for SSH-based FMU+canio updates
Several helper scripts assumes bash is available at /bin/bash. That breaks on systems
such as NixOS, where bash is resolved from PATH instead of a fixed /bin location and
causes failures like `bad interpreter` during `make format`, e.g., on my host machine:
```sh
$ make format
/PX4-Autopilot/Tools/astyle/check_code_style.sh: /PX4-Autopilot/Tools/astyle/fix_code_style.sh: /bin/bash: bad interpreter: No such file or directory
```
This change switches these entrypoints to `#!/usr/bin/env bash` so they locate bash properly.
No functional changes intended.
Signed-off-by: Onur Özkan <work@onurozkan.dev>