Add modular dev environment installer, dotfiles, and desnap script

Adds a TUI-driven, rollback-capable installer (install/install.sh +
install/modules/*.sh) covering JS/Python/systems toolchains, dev tooling,
browsers, chat apps, GNOME extras, and misc setup (wakatime key, ssh/gpg
perms, apt mirror benchmarking), all sourced from each vendor's official
install method. bootstrap.sh stows the zsh/git/tmux/vscode dotfiles and
runs the installer; desnap.sh purges snapd and replaces default snaps with
apt/Flatpak equivalents.

install/modules/chrome.sh

@@ -0,0 +1,14 @@
+install_chrome() {
+  if has_cmd google-chrome-stable; then
+    ok "chrome already installed"
+    return
+  fi
+
+  local deb
+  deb=$(mktemp --suffix=.deb)
+  curl -fsSL https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb -o "$deb"
+  apt_update_once
+  sudo apt-get install -y "$deb"
+  rm -f "$deb"
+  rollback_push "sudo apt-get remove -y google-chrome-stable"
+}