Add missing Qt6 xcb platform dependencies

Added libxkbcommon-x11-0, libxcb-image0, libxcb-render0,
libxcb-shm0, libxcb-sync1, libxcb-xfixes0, libxcb-xkb1,
libx11-xcb1, libfontconfig1, libfreetype6

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Dockerfile

@@ -11,18 +11,29 @@ LABEL description="Ramble - AI-powered structured field extraction GUI"
 # Install system dependencies
 RUN apt-get update && apt-get install -y --no-install-recommends \
     plantuml \
-    # Qt6 dependencies (Debian Trixie package names)
+    # Qt6 xcb platform plugin dependencies
     libgl1 \
     libegl1 \
     libxkbcommon0 \
+    libxkbcommon-x11-0 \
     libdbus-1-3 \
+    libxcb1 \
     libxcb-cursor0 \
     libxcb-icccm4 \
+    libxcb-image0 \
     libxcb-keysyms1 \
-    libxcb-shape0 \
-    libxcb-xinerama0 \
-    libxcb-randr0 \
+    libxcb-render0 \
     libxcb-render-util0 \
+    libxcb-shape0 \
+    libxcb-shm0 \
+    libxcb-sync1 \
+    libxcb-xfixes0 \
+    libxcb-xinerama0 \
+    libxcb-xkb1 \
+    libxcb-randr0 \
+    libx11-xcb1 \
+    libfontconfig1 \
+    libfreetype6 \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app