Add installation and uninstallation scripts with updated README instructions

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

install.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+SRC_BIN="$SCRIPT_DIR/home/.local/bin/nextdns-tray"
+SRC_DESKTOP="$SCRIPT_DIR/home/.local/share/applications/nextdns-tray.desktop"
+SRC_ICON="$SCRIPT_DIR/home/.local/share/icons/nextdns.png"
+
+DEST_BIN="$HOME/.local/bin"
+DEST_APPS="$HOME/.local/share/applications"
+DEST_ICONS="$HOME/.local/share/icons"
+DEST_AUTOSTART="$HOME/.config/autostart"
+
+ENABLE_AUTOSTART=0
+if [[ "${1:-}" == "--autostart" ]]; then
+  ENABLE_AUTOSTART=1
+fi
+
+if [[ ! -f "$SRC_BIN" || ! -f "$SRC_DESKTOP" || ! -f "$SRC_ICON" ]]; then
+  echo "Error: expected files were not found under the repository home/ directory."
+  exit 1
+fi
+
+mkdir -p "$DEST_BIN" "$DEST_APPS" "$DEST_ICONS"
+
+install -m 0755 "$SRC_BIN" "$DEST_BIN/nextdns-tray"
+install -m 0644 "$SRC_DESKTOP" "$DEST_APPS/nextdns-tray.desktop"
+install -m 0644 "$SRC_ICON" "$DEST_ICONS/nextdns.png"
+
+if [[ "$ENABLE_AUTOSTART" -eq 1 ]]; then
+  mkdir -p "$DEST_AUTOSTART"
+  install -m 0644 "$DEST_APPS/nextdns-tray.desktop" "$DEST_AUTOSTART/nextdns-tray.desktop"
+fi
+
+if command -v update-desktop-database >/dev/null 2>&1; then
+  update-desktop-database "$DEST_APPS" >/dev/null 2>&1 || true
+fi
+
+echo "Installed NextDNS Tray Icon to $HOME/.local"
+if [[ "$ENABLE_AUTOSTART" -eq 1 ]]; then
+  echo "Autostart enabled"
+else
+  echo "Autostart not enabled (use --autostart to enable)"
+fi