TUIs feature-gate on TERM_PROGRAM_VERSION (Neovim's terminal
autodetection, bat/delta styling hints, etc). We already set
TERM_PROGRAM=Orca but left the version unset, so tools can't distinguish
Orca builds or tell when version-gated features are safe to enable.
Seed process.env.ORCA_APP_VERSION from app.getVersion() at main startup
and read it from both PTY spawn sites (main-side local-pty-provider and
the daemon-side pty-subprocess, which inherits env via fork). Keeps
providers/local-pty-provider.ts free of electron imports.