Add swarm bootload info and flash (unicast)

[evoggy]

Adds cfcli swarm bootload info and cfcli swarm bootload flash.

This is unicast only for now: the Crazyflies are flashed one after another, the same way cfcli bootload flash flashes one. Broadcast flashing, where every Crazyflie with a new enough bootloader receives each image at the same time, will follow in a separate PR. It depends on bitcraze/cfloader-rs#3, which isn't merged or released yet.

What's in it

cfcli swarm bootload flash

cfcli swarm bootload flash --release 2026.08
cfcli swarm bootload flash --bin stm32-fw=cf21bl.bin --cf CF-01,CF-02

• Arguments: takes the same --release, --zip, --bin and --targets as bootload flash, plus the usual --cf, --exclude and --swarm.
• Checks before touching any Crazyflie: the release, the files and the targets.
• Checks before flashing anything: the firmware for every platform in the swarm is prepared up front, so a --zip built for another platform stops the command instead of failing halfway.
• Flashing: one Crazyflie after another, with the normal flash output under a header per Crazyflie and a summary table at the end. A Crazyflie that fails doesn't stop the others, and the exit code follows the swarm rules (0, the usual code if all failed the same way, otherwise 50). A unicast flash keeps the radio busy, so flashing several at once wouldn't be faster.

Swarms with several platforms

STM32 images differ between platforms (a Crazyflie 2.1 and a 2.1 Brushless can't run each other's), and nRF51 images differ for some of them:

• --release: downloaded per platform, so every Crazyflie gets its own platform's files.
• STM32 and nRF51 images given with --bin: only flashed when all the Crazyflies to flash have the same platform. Otherwise the command stops before flashing anything, listing the platforms and their Crazyflies.
• Deck firmware: works whatever the Crazyflie, so it still goes to all of them.
• --platform cf21|cf21bl|bolt11|flapper|tag: flashes only the Crazyflies of one platform and skips the rest, so a mixed swarm is flashed one platform at a time.

cfcli swarm bootload info

CF    | nRF51 bootloader | STM32 bootloader | Broadcast
------+------------------+------------------+-----------
CF-01 | 0x11             | 0x11             | yes
CF-02 | 0x10             | 0x10             | no

• Shows the bootloader versions of each Crazyflie, and whether both bootloaders can take broadcast flashing (protocol 0x11, from Add broadcast flashing and CRC commands (protocol 0x11) crazyflie2-nrf-bootloader#12 and Add PAGE_CRC and RANGE_CRC commands (protocol 0x11) crazyflie2-stm-bootloader#4).
• Unlike bootload info, it restarts each Crazyflie back into its firmware afterwards.
• It checks first that each Crazyflie answers, and gives each one 15 s, so one that hangs can't hold up the rest.
• --csv is supported.

Refactoring

• Shared flash handling: the release, --bin and --targets handling of bootload flash moves out of main.rs into utils/flash_source.rs, and the four arguments into FirmwareSourceArgs, shared by both commands. bootload flash works as before.
• Platform names: shared by both commands. An unknown --platform for bootload flash --cold now exits 30 instead of 1.
• Smaller changes: bootloader::bootloader_versions() reads both versions and restarts into the firmware, and FirmwareUpgrade is Clone.

Fix: bootloader protocol version

get_info read the protocol version from byte 1 of the GET_INFO answer, which is the GET_INFO command echoed back. So every bootloader reported 0x10, and bootload info always printed "Protocol Version: 16". It also read the CPU ID as 2 bytes instead of 12. The answer is [target, GET_INFO, page size, buffer pages, flash pages, start page, 12-byte CPU ID, protocol version], as cfloader and cflib read it. The version now comes from byte 22 (0 for bootloaders from before it existed), and the CPU ID is printed in full. This affects bootload info too.

Testing

• Unit tests: 61. The new ones cover the platform names, which --bin keys are platform-bound, and the refusal for mixed platforms.
• Without flashing anything:
  • An unknown release (20), an unknown target (30, after the release download, before flashing), an unknown platform (30), and --platform with no matching Crazyflie (20).
  • A --bin that can't be read stops before flashing, after reading the platforms.
  • Crazyflies that don't answer give 10 for both commands.
• On hardware, with 3 Crazyflie 2.1 Brushless on 3 Crazyradios:
  • swarm bootload flash was run on the swarm.
  • swarm bootload info showed protocol 0x11 on both bootloaders after the version fix (0x10 before it). The Crazyflies were back in their firmware afterwards.