Restore support for Felicita Arc scale and fix related bugs

[A-TWJ]

Felicita Arc support had been dropped due to occasional changing display modes on connect.

Root cause

The Acaia IDENTIFY/heartbeat handshake was sent to every scale. The Felicita
parses each received byte as a command, and IDENTIFY contains 0x31..0x35 —
its mode-select keys — so every (re)connect was switching the scale's mode.

Changes

• Dedicated FELICITA scale type instead of relying on GENERIC.
• Acaia handshake/heartbeat sent only to Acaia scales ( I assume bookoo scales doesn't need them, but if i was wrong it is easy to include them).
• Felicita commands sent as single ASCII bytes; lengths via sizeof().
• Set the scale to a known weight+timer mode on init.

Testing

Disconnected/reconnected the ESP repeatedly, watching the scale's mode and the
UART output:

• Old code: mode changes on some (re)connects.
• New code: no mode changes across many cycles; UART readings consistent.

The forced weight+timer mode on init is now redundant and can be removed.

Not yet tested

• only connect/init were tested on Felicita scales — shotStopper brew-by-weight operation needs testing ( I don't own a supported espresso machine).

• Other scales (Acaia old/new, BooKoo/generic) need re-testing for connectivity
  and operation.

  I kept LIBRARY_VERSION same with added note as am not sure how you handle version control in this project.