v0.5.7 — classic snap drives the deck + one-click device access

Added

• Classic-confinement Snap that actually drives the deck. The deck is
  controlled over /dev/hidraw, which strict snap confinement cannot grant —
  the classic build reaches the device just like the .deb does.
• One-click "Enable device access" button in the Snap. A snap can't install
  the udev rule the deck needs, so the classic snap bundles the rule and, when
  the device isn't reachable, offers a button that installs it via pkexec
  (graphical auth) and reconnects live — no terminal, no relaunch.

Fixed

• Snap boots reliably: bundle the Python interpreter + stdlib and pin
  PYTHONHOME (core24's base provides python3.12, so snapcraft otherwise
  prunes it from the classic payload — fatal at runtime).
• Snap shows the device-access hint even when the deck enumerates over libusb
  with empty firmware (the false "connected" used to suppress it).

Changed

• Packaging: debian/source/options keeps build artifacts (dist/, *.snap,
  caches) out of the native source tarball.
• Docs: SNAP.md documents the working classic build; the README leads with the
  PPA and flags that the current store snap (strict) can't drive the deck.

Install

PPA / .deb — recommended (installs the udev rule for you, drives the deck out of the box):

sudo add-apt-repository ppa:zoutmax/fifine
sudo apt install fifine-control-deck

…or download a .deb below (amd64 / arm64).

Snap: the classic build (with device control + the one-click access button)
is pending Snap Store classic-confinement review; the snap currently on the
store is strict-confined and opens but cannot drive the deck.

Full Changelog: v0.5.6...v0.5.7