docker_update: prune dangling images after pull (both normal and remainder modes)

Daily restarts create orphaned images that were never cleaned up.
Added docker image prune -f section matching docker_update_remaining.sh pattern.
Prune runs each cycle so orphans from the previous day's restart are removed daily
rather than waiting for the weekly docker_update_remaining.sh sweep.

Docker_Essentials/docker_update.sh

@@ -30,7 +30,7 @@
 #     DAILY_RESTART_CONTAINERS       — already updated daily
 #     emby + critical-data profiles  — updated inline by the weekly sync window
 #     FALLBACK_*_TIER*               — owned by the remote server's update cycle
-#   Pull → compare → restart if updated → prune dangling images.
+#   Pull → compare → prune dangling images.
 #
 # ==============================================================================================
 # DESIGN PRINCIPLES
@@ -313,6 +313,21 @@ done
 
 END=$(date +%s)
 
+# ==============================================================================================
+# ━━━ Prune Old Images ━━━
+# ==============================================================================================
+echo ""
+echo "━━━ $ICON_SYNC Pruning Dangling Images — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
+
+if [[ "$DRY_RUN" == true ]]; then
+    warn "DRY RUN — would prune dangling images"
+    PRUNED_SUMMARY="(dry run)"
+else
+    PRUNED_OUTPUT=$(docker image prune -f 2>&1)
+    [[ "$ENABLE_LOGGING" == "true" ]] && echo "$PRUNED_OUTPUT" | sed 's/^/  /'
+    PRUNED_SUMMARY=$(echo "$PRUNED_OUTPUT" | grep -E "^Total reclaimed" || echo "nothing reclaimed")
+fi
+
 # ==============================================================================================
 # ━━━ Summary ━━━
 # ==============================================================================================
@@ -330,6 +345,7 @@ fi
 [[ ${#UP_TO_DATE[@]} -gt 0 ]] && log "$ICON_RUNNING    Up to date:  ${#UP_TO_DATE[@]}"
 [[ ${#SKIPPED[@]} -gt 0 ]]    && log "$ICON_WARN       Skipped:     ${#SKIPPED[@]}"
 [[ ${#FAILED[@]} -gt 0 ]]     && echo "$ICON_ERROR      Failed:      ${FAILED[*]}"
+echo "$ICON_SYNC       Pruned:      ${PRUNED_SUMMARY:-none}"
 
 if [[ "$DRY_RUN" == true ]]; then
     warn "DRY RUN — no images pulled"