refactor: move backup/restore worker scripts to extras/ as source files

Replace embedded heredocs in the three backup service installers with
cp from versioned source files in extras/:

  extras/backup_kopia.sh   — Kopia worker (was inline in services/backup.sh)
  extras/backup_borg.sh    — Borg worker  (was inline in services/borg-backup.sh)
  extras/backup_gaming.sh  — gaming saves worker (was inline in services/gaming-backup.sh)
  extras/restore_kopia.sh  — unified Kopia restore (multi-dest + single-dest)
  extras/restore_borg.sh   — unified Borg restore with destination picker

Each installer now does `cp extras/<script>.sh $DIR/<script>.sh` instead of
writing the script inline. Workers and restore scripts are now readable in the
repo rather than buried in heredocs.

Restore scripts are installed flat into the service directory root:
  ~/docker/backup/backup_kopia.sh   ~/docker/backup/restore_kopia.sh
  ~/docker/borg-backup/backup_borg.sh   ~/docker/borg-backup/restore_borg.sh
  ~/docker/gaming-backup/backup_gaming.sh   ~/docker/gaming-backup/restore_kopia.sh

The new restore scripts handle destination selection internally, so a single
script replaces the old per-destination restore/<dest>/ layout.

Also fixes `local` used outside a function in restore_kopia.sh and
restore_borg.sh (destination picker loop), and removes the now-superseded
extras/restore_kopia_backup.sh and extras/restore_borg_backup.sh.

https://claude.ai/code/session_019XgsQ13XKm4Zj3cNsDNwHj

extras/backup_gaming.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+# extras/backup_gaming.sh — Kopia gaming-saves worker (no service downtime).
+# Installed to ~/docker/gaming-backup/backup_gaming.sh by the gaming-backup installer.
+#
+#   sudo ./backup_gaming.sh             run a backup now
+#   sudo ./backup_gaming.sh snapshots   list snapshots
+#   sudo ./backup_gaming.sh policy      show retention/ignore policy
+#
+# Nothing is stopped: Minecraft worlds are flushed to disk (save-all) first.
+# Reads backup.conf from the same directory.
+set -uo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CONF="${BACKUP_CONF:-$HERE/backup.conf}"
+[ -f "$CONF" ] || { echo "Config not found: $CONF (re-run: sudo setup.sh gaming-backup)"; exit 1; }
+# shellcheck source=/dev/null
+source "$CONF"
+
+export KOPIA_PASSWORD
+log() { echo "[$(date '+%F %T')] $*"; }
+k()   { "$KOPIA" --config-file="$KOPIA_CONFIG" "$@"; }
+
+if ! k repository status >/dev/null 2>&1; then
+    log "ERROR: not connected to a repository — re-run the gaming-backup service"
+    exit 1
+fi
+
+case "${1:-run}" in
+    snapshots) k snapshot list; exit 0 ;;
+    policy)    k policy show --global; exit 0 ;;
+esac
+
+log "===== Gaming backup starting ====="
+
+if [ -n "${MC_BASE_DIR:-}" ] && command -v docker >/dev/null 2>&1; then
+    _flushed=0
+    for d in "$MC_BASE_DIR"/*/; do
+        [ -f "${d}Dockerfile" ] && grep -qs itzg "${d}Dockerfile" || continue
+        name="$(basename "$d")"
+        if docker ps --format '{{.Names}}' 2>/dev/null | grep -qx "$name"; then
+            log "Flushing Minecraft world '$name' (save-all)..."
+            docker exec "$name" mc-send-to-console save-all flush 2>/dev/null \
+                || docker exec "$name" rcon-cli save-all 2>/dev/null || true
+            _flushed=1
+        fi
+    done
+    [ "$_flushed" = 1 ] && sleep 5
+fi
+
+rc=0
+snap() {
+    local label="$1" path="$2"
+    if [ -z "$path" ] || [ ! -e "$path" ]; then
+        log "skip $label — not found: ${path:-<unset>}"; return
+    fi
+    log "Snapshotting $label: $path"
+    if ! k snapshot create --description="gaming: $label" "$path"; then
+        log "WARNING: snapshot failed for $label"; rc=1
+    fi
+}
+
+if [ -n "${MC_BASE_DIR:-}" ]; then
+    for d in "$MC_BASE_DIR"/*/; do
+        [ -f "${d}Dockerfile" ] && grep -qs itzg "${d}Dockerfile" && [ -d "${d}data" ] || continue
+        nm="$(basename "$d")"
+        case "$nm" in minecraft*) lbl="$nm" ;; *) lbl="minecraft-$nm" ;; esac
+        snap "$lbl" "${d}data"
+    done
+fi
+[ "${BACKUP_SAVES:-no}" = yes ]  && snap "emulator-saves" "$GAME_STORAGE_DIR/saves"
+[ "${BACKUP_STEAM:-no}" = yes ]  && snap "steam-userdata" "$GAME_STORAGE_DIR/steam"
+[ "${BACKUP_MEDIA:-no}" = yes ]  && snap "es-de-media"    "$GAME_STORAGE_DIR/media"
+[ "${BACKUP_WOLF:-no}"  = yes ]  && snap "wolf-state"     "$WOLF_STATE_DIR"
+
+if [ "${REMOTE_TYPE:-none}" != "none" ] && [ -n "${REMOTE_TYPE:-}" ]; then
+    log "Mirroring repository to remote ($REMOTE_TYPE)..."
+    # shellcheck disable=SC2086
+    if ! k repository sync-to "$REMOTE_TYPE" $REMOTE_ARGS; then
+        log "WARNING: remote mirror failed"; rc=1
+    fi
+fi
+
+if [ "$rc" -eq 0 ]; then
+    log "===== Gaming backup complete ====="
+else
+    log "===== Gaming backup finished WITH WARNINGS ====="
+fi
+exit "$rc"