v3.8.2 — flashing reliability + UX

v3.8.2 — flashing reliability + UX

A host-side flashing-tooling release. The on-device firmware is byte-identical
to v3.8.1 (same kernel and bootloader binaries), so there is nothing to re-flash
for functionality — pull the updated scripts and you're set. Re-flashing simply
updates the version banner to v3.8.2.

Fixed

• flash_install_rtl8196e.sh no longer mislabels a successful auto-flash as
  "manual flash required". The pre-upload ICMP probe that classifies the
  bootloader could miss on a single dropped/raced ping and fall through to the
  manual-FLW path — even though a custom (V2.x) bootloader had already auto-flashed
  the image and rebooted. The probe now polls (~10 s) instead of pinging once,
  and the upload now happens immediately after the gateway enters the bootloader
  (the image is built before boothold on the upgrade path, so nothing masks the
  bootloader's settle window). Thanks @MaxRower for the clear report in #115.

• Clearer fallback guidance. When the script does fall back to the manual path,
  it now tells you that a custom bootloader may have auto-flashed on its own — check
  ping / ssh to the gateway (wait ~2 min for the reboot) before re-flashing,
  instead of the previous, misleading "nothing was changed".

Added

• --boot-ip / BOOT_IP accept a hostname. A name is resolved host-side to a
  dotted-quad before use (the on-device handoff needs a literal IPv4). A dotted-quad
  still passes through unchanged. Works in both flash_install_rtl8196e.sh and
  flash_remote.sh.

Notes

• Upgrade path (flash_install_rtl8196e.sh <LINUX_IP>): the 16 MiB image is now
  assembled while Linux is still up, so the gateway no longer sits idle in download
  mode during the build, and declining the final confirmation leaves Linux intact.