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-share-tui

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -euo pipefail
+FOLDER="${1:-}"
+[[ -n "$FOLDER" ]] || { echo "Usage: backtunnel-share-tui <folder>"; exit 1; }
+
+read -r -p "Remote (user@host or user:host) [user@vps.example.com]: " REMOTE
+REMOTE="${REMOTE:-user@vps.example.com}"
+
+read -r -p "Share duration (30m/2h/1d) [2h]: " DUR
+DUR="${DUR:-2h}"
+
+read -r -p "Tunnel port on remote [2222]: " TPORT
+TPORT="${TPORT:-2222}"
+
+read -r -p "Local sshd port to expose [22]: " LPORT
+LPORT="${LPORT:-22}"
+
+read -r -p "Print invite line for chat? (y/N): " yn
+INV=; [[ "${yn,,}" == "y" ]] && INV="-i"
+
+QR=
+if [[ -n "$INV" ]]; then
+  read -r -p "Show QR code for the invite? (y/N): " yq
+  [[ "${yq,,}" == "y" ]] && QR="--qr"
+fi
+
+read -r -p "Invite: suggested mount point [/mnt/remote-rssh]: " MP
+MP="${MP:-/mnt/remote-rssh}"
+
+echo
+echo "Running: backtunnel-share '$FOLDER' with '$REMOTE' for '$DUR' -p '$TPORT' -l '$LPORT' ${INV:+-i} ${QR:+--qr} --invite-mount '$MP'"
+exec backtunnel-share "$FOLDER" with "$REMOTE" for "$DUR" -p "$TPORT" -l "$LPORT" ${INV:+-i} ${QR:+--qr} --invite-mount "$MP"