Repro build cleanup

[dmonakhov]

Here are trivial cleanups for reproducible build, Commits are tiny so feel free to squash it in to one if required.

TOC

Trivial cleanup for reproducible build examples

• README: Update examples to use latest's release
• README: fix repro build example

Improve check repro human readability

• check-repro: dump published resource checksum

IMHO with explicit csum logging verification becomes more intuitive , see:

Comparing against: /tmp/checkout/firmware/releases/2026-07-01T1727-v1.4.1Q-q1-coldcard.dfu
SHA256: 1139f2192602711ca182cec0e40f825365f4f617dd672eb452a2aa07d3af95e7 /tmp/checkout/firmware/releases/2026-07-01T1727-v1.4.1Q-q1-coldcard.dfu
test -n "/tmp/checkout/firmware/releases/2026-07-01T1727-v1.4.1Q-q1-coldcard.dfu" -a -f /tmp/checkout/firmware/releases/2026-07-01T1727-v1.4.1Q-q1-coldcard.dfu
rm -f -f check-fw.bin check-bootrom.bin
signit split /tmp/checkout/firmware/releases/2026-07-01T1727-v1.4.1Q-q1-coldcard.dfu check-fw.bin check-bootrom.bin
start 293 for 1073152 bytes: Firmware => check-fw.bin
signit check check-fw.bin
     magic_value: 0xcc001234
       timestamp: 2026-07-01 17:28:10 UTC
  version_string: 1.4.1Q
      pubkey_num: 1
 firmware_length: 1073152
   install_flags: 0x0 =>
       hw_compat: 0x10 => Q1
         best_ts: b'\x00\x00\x00\x00\x00\x00\x00\x00'
          future: 0000000000000000 ... 0000000000000000
       signature: be7583eeef90b112 ... d840ffb353891968
sha256^2: 6a7f10b28faacbc319b9b632e1d4978664164a6ec58520ec6f12cba563a9b818