Add installation and uninstallation scripts with updated README instructions

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

uninstall.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  cat <<'EOF'
+Usage:
+  ./uninstall.sh [--dry-run]
+
+Options:
+  --dry-run   Show what would be removed without deleting files.
+EOF
+}
+
+DRY_RUN=0
+case "${1:-}" in
+  "") ;;
+  --dry-run) DRY_RUN=1 ;;
+  -h|--help)
+    usage
+    exit 0
+    ;;
+  *)
+    echo "Unknown option: ${1}" >&2
+    usage >&2
+    exit 1
+    ;;
+esac
+
+TARGETS=(
+  "$HOME/.local/bin/nextdns-tray"
+  "$HOME/.local/share/applications/nextdns-tray.desktop"
+  "$HOME/.local/share/icons/nextdns.png"
+  "$HOME/.config/autostart/nextdns-tray.desktop"
+)
+
+remove_file() {
+  local path="$1"
+  if [[ -e "$path" ]]; then
+    if [[ "$DRY_RUN" -eq 1 ]]; then
+      echo "Would remove: $path"
+    else
+      rm -f "$path"
+      echo "Removed: $path"
+    fi
+  else
+    echo "Not present: $path"
+  fi
+}
+
+for path in "${TARGETS[@]}"; do
+  remove_file "$path"
+done
+
+if [[ "$DRY_RUN" -eq 0 ]]; then
+  if command -v update-desktop-database >/dev/null 2>&1; then
+    update-desktop-database "$HOME/.local/share/applications" >/dev/null 2>&1 || true
+  fi
+  echo "Uninstall complete"
+else
+  echo "Dry run complete"
+fi