enveigh for Linux: terminal edition

Runtime: Ubuntu 24.04 or newer, or current Arch Linux; matching CPU architecture.
Dependencies: pass, GnuPG, pinentry, Git, OpenSSL 3, libsodium, libcurl, glibc, libstdc++ and libgcc.
Swift libraries and the bundled agent skill are included beside the executable.

Start as your normal user, never root:
  enveigh                          # sets up, starts the service and unlocks

The first run picks (or creates) your GPG key, starts and enables the user service,
then unlocks through pinentry. Without systemd it starts `enveigh serve` in the background.
Use `enveigh unlock` to unlock from a separate interactive terminal.
Start a task session before a long run. GPG cache expiry will not interrupt it.
The service never opens pinentry. Restarting/stopping it ends all task sessions.
Package installation itself does not enable or restart the service, connect agents, or
change GPG settings. Restart deliberately after an upgrade when runs finish.
An existing service and your TUI must use the same HOME/XDG_DATA_HOME/GNUPGHOME.
For a custom GNUPGHOME, configure it in a systemd user-service override too.

See linux-user-guide.md for lock behavior, clipboard privacy, upgrades and recovery.
See the release evidence at https://enveigh.com/linux.
