[NO-TICKET] Add Start VNC Streaming Script to scripts/ (#4304)

Co-authored-by: Shuchang Zheng <wintonzheng0325@gmail.com>

scripts/start_vnc_streaming.sh

@@ -0,0 +1,78 @@
+#!/bin/bash
+# Start VNC streaming services for Skyvern
+#
+# This script sets up the complete VNC streaming stack:
+# - Xvfb (virtual X11 display)
+# - x11vnc (VNC server for the display)
+# - websockify (WebSocket-to-VNC proxy)
+
+set -euo pipefail
+
+readonly DISPLAY_NUM=":99"
+readonly SCREEN_GEOMETRY="1920x1080x24"
+readonly VNC_PORT="5900"
+readonly WS_PORT="6080"
+
+log() {
+    printf '%s\n' "$*"
+}
+
+is_running_exact() {
+    local process_name="$1"
+    pgrep -x "$process_name" > /dev/null 2>&1
+}
+
+is_running_match() {
+    local pattern="$1"
+    pgrep -f "$pattern" > /dev/null 2>&1
+}
+
+ensure_running() {
+    local service_label="$1"
+    local running_check_type="$2"  # "exact" | "match"
+    local check_value="$3"
+    local start_cmd="$4"
+
+    if [[ "$running_check_type" == "exact" ]]; then
+        if is_running_exact "$check_value"; then
+            log "$service_label already running"
+            return 0
+        fi
+    else
+        if is_running_match "$check_value"; then
+            log "$service_label already running"
+            return 0
+        fi
+    fi
+
+    log "Service $service_label not running. Starting..."
+    eval "$start_cmd"
+    log "$service_label started"
+}
+
+log "Starting VNC streaming services for Skyvern..."
+log ""
+
+ensure_running \
+  "Xvfb" "exact" "Xvfb" \
+  "Xvfb $DISPLAY_NUM -screen 0 $SCREEN_GEOMETRY > /dev/null 2>&1 &"
+
+ensure_running \
+  "x11vnc" "exact" "x11vnc" \
+  "x11vnc -display $DISPLAY_NUM -bg -nopw -listen localhost -xkb -forever > /dev/null 2>&1"
+
+ensure_running \
+  "websockify" "match" "websockify.*${WS_PORT}" \
+  "websockify $WS_PORT localhost:${VNC_PORT} --daemon > /dev/null 2>&1"
+
+
+log ""
+log "🎉 VNC streaming services are now running!"
+log ""
+log "Configuration:"
+log "  - Xvfb display: ${DISPLAY_NUM}"
+log "  - VNC server: localhost:${VNC_PORT}"
+log "  - WebSocket proxy: localhost:${WS_PORT}"
+log ""
+log "To stop services:"
+log "  pkill x11vnc && pkill websockify"