Set DEBIAN_FRONTEND=noninteractive in Dockerfile

tzdata was prompting for a timezone interactively during apt-get install,
which hangs the Dokploy build. Pin TZ=Etc/UTC and skip the prompt.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Dockerfile

@@ -3,7 +3,10 @@ FROM mcr.microsoft.com/playwright:v1.57.0-jammy
 
 # Install Xvfb (virtual display), x11vnc (VNC server) and noVNC (web-based VNC client)
 # so a human can log in to Reddit through the dashboard.
+ENV DEBIAN_FRONTEND=noninteractive \
+    TZ=Etc/UTC
 RUN apt-get update && apt-get install -y --no-install-recommends \
+    tzdata \
     xvfb \
     x11vnc \
     novnc \