v1.61.0

Added

• A home screen that asks what you came for: Printers or Reader. The
  printer list is one tap in, with a chevron back; the account and Wi-Fi state
  live on the home screen, which is where the device starts.
• Reader mode: put a spool on the pad and read it - colour, material,
  brand, finish, diameter, the two temperature windows, what is left on the
  spool, and whether the chip proved itself genuine. It is the NFC tester's
  question without the NFC tester's thirty fields, which stay in Settings.
• A Write row on the home screen, greyed and marked as coming: writing a
  spool from the device itself is not built yet, and the row says so rather
  than appearing one day and moving everything under it.

Changed

• The account and Wi-Fi icons are on the home screen only. The printer list
  carries a back chevron, its title and the gear instead: 240 px does not hold
  all six, and the title was running under the icons.
• Settings returns to the screen the gear was pressed on.
• The reader row wears the same amber as the reader screen: one subject, one
  colour.
• Internal: a guard now fails the build when the device and the setup portal
  disagree about how many bars a signal is worth. The scale is written in two
  languages, in two files, and nothing but a person holding a phone beside the
  device would have noticed them drifting apart.

Fixed

• Two NFC icons on one screen shared a single pixel buffer, so the second one
  drawn overwrote the first and both wore the second's colour. Each canvas icon
  now owns its buffer and frees it with the object.
• scripts/flash.sh no longer claims no board is plugged in when the
  PlatformIO virtualenv has lost its esptool module. It falls back to the
  copy that ships with the platform, and says so plainly if neither is there.