Introduce terminal-based workflows for BackTunnel via TUI scripts and service menus

Add `backtunnel-open-term`, `backtunnel-share-tui`, and `backtunnel-access-tui` scripts for terminal-based interaction. Update Dolphin service menus to enable TUI workflows, with improved terminal detection logic. Enhance installation and uninstallation scripts to handle new files. Update README with terminal workflow details and logging information.

scripts/backtunnel-open-term

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+# Open a command in the user's available terminal emulator, with logging.
+# Usage: backtunnel-open-term <cmd> [args...]
+set -euo pipefail
+
+LOG_DIR="${XDG_STATE_HOME:-$HOME/.local/state}/backtunnel"
+[[ -d "$LOG_DIR" ]] || mkdir -p "$LOG_DIR"
+LOG_FILE="${LOG_DIR}/servicemenu.$(date +%Y%m%d-%H%M%S).log"
+
+# Simple rotation: keep the last 10 files
+ls -1t "$LOG_DIR"/servicemenu.*.log 2>/dev/null | awk 'NR>10{print}' | xargs -r rm -f
+
+cmd=( "$@" )
+{
+  echo "=== BackTunnel servicemenu ==="
+  echo "Time: $(date -Is)"
+  echo "PWD:  $(pwd)"
+  echo "User: $(id -un) (uid=$(id -u))"
+  echo "Cmd:  ${cmd[*]}"
+  echo "Env:  BACKTUNNEL_DEBUG=${BACKTUNNEL_DEBUG:-}  SHELL=${SHELL:-}  DISPLAY=${DISPLAY:-}"
+  echo
+
+  # Prefer Konsole on KDE sessions; otherwise probe common terminals
+  detect_term() {
+    if [[ -n "${KDE_FULL_SESSION:-}" ]] && command -v konsole >/dev/null 2>&1; then
+      echo "konsole"; return
+    fi
+    for t in kitty alacritty kgx gnome-terminal tilix xfce4-terminal konsole xterm; do
+      if command -v "$t" >/dev/null 2>&1; then echo "$t"; return; fi
+    done
+    echo ""  # none
+  }
+
+  term="$(detect_term)"
+  echo "Chosen terminal: ${term:-<none>}"; echo
+
+  # Run command in terminal (use hold/noclose if supported)
+  case "$term" in
+    konsole)         exec konsole --noclose -e "${cmd[@]}" ;;
+    kitty)           exec kitty -e "${cmd[@]}" ;;
+    alacritty)       exec alacritty -e "${cmd[@]}" ;;
+    gnome-terminal)  exec gnome-terminal -- bash -lc "exec \"${cmd[0]}\" ${cmd[@]:1}" ;;
+    kgx)             exec kgx -- bash -lc "exec \"${cmd[0]}\" ${cmd[@]:1}" ;;  # GNOME Console
+    tilix)           exec tilix -e "${cmd[@]}" ;;
+    xfce4-terminal)  exec xfce4-terminal -e "${cmd[@]}" ;;
+    xterm)           exec xterm -hold -e "${cmd[@]}" ;;
+    *)
+      echo "No terminal emulator found. Running in background (nohup)."
+      nohup "${cmd[@]}" >/dev/null 2>&1 &
+      echo "Started in background (pid=$!)."
+      echo "Log: $LOG_FILE"
+      exit 0
+      ;;
+  esac
+} | tee -a "$LOG_FILE"