Revert v1.1.0 — graphical installer

What's new

• Graphical installer — a small local web UI (gui/) that wraps the whole revert
  lifecycle (doctor · setup · game data · build · play · update) with a live output
  console. Pure Go, zero native dependencies, a single static binary that
  cross-compiles to Linux / Steam Deck / Windows / macOS.

  cd gui && go build -o revert-gui . && ./revert-gui

  It opens your browser, finds the toolkit automatically, and streams each command's output
  as it runs. Bound to 127.0.0.1; runs revert subcommands from a fixed whitelist. The CLI
  stays fully supported — the GUI just drives it.

Everything from v1.0.x (three lanes, the QOL mod suite, Steam Deck, acquire-hq, revert update) is unchanged. MIT. Bring your own THUG2 copy.