Add custom guacd Dockerfile with FreeRDP 3.x to fix Windows 11 NLA crash

The official guacamole/guacd image ships FreeRDP 2.x, which crashes
silently when connecting to Windows 11 22H2+ hosts due to NLA/CredSSP
cipher-suite changes. FreeRDP 3.x resolves this.

- docker/guacd.Dockerfile: builds guacamole-server 1.6.0 from source on
  Ubuntu 24.04 against freerdp3-dev (FreeRDP 3.5.1+); uses
  CPPFLAGS=-Wno-error=deprecated-declarations to suppress upstream
  deprecation warnings in freerdp3 headers
- docker-compose.yml: switch guacd service from official image to local build

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/guacd.Dockerfile

@@ -0,0 +1,66 @@
+# syntax=docker/dockerfile:1
+#
+# Custom guacd image built against FreeRDP 3.x on Ubuntu 24.04.
+#
+# Why: The official guacamole/guacd image uses FreeRDP 2.x, which crashes
+# silently when connecting to Windows 11 22H2+ hosts due to NLA/CredSSP
+# cipher-suite changes introduced by Microsoft. FreeRDP 3.x fixes this.
+# guacamole-server 1.6.0 (June 2025) has explicit FreeRDP 3.x support.
+# Ubuntu 24.04 ships freerdp3-dev (FreeRDP 3.5.1+) in its universe repo.
+#
+# Note: FreeRDP 3.x support in guacamole is currently marked experimental
+# for some features (RemoteApp), but basic RDP/NLA works correctly.
+
+FROM ubuntu:24.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Build dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    autoconf \
+    automake \
+    build-essential \
+    ca-certificates \
+    curl \
+    freerdp3-dev \
+    libcairo2-dev \
+    libjpeg-turbo8-dev \
+    libossp-uuid-dev \
+    libpango1.0-dev \
+    libpng-dev \
+    libpulse-dev \
+    libssl-dev \
+    libssh2-1-dev \
+    libtelnet-dev \
+    libtool \
+    libvncserver-dev \
+    libwebp-dev \
+    libwebsockets-dev \
+    pkgconf \
+    && rm -rf /var/lib/apt/lists/*
+
+ARG GUACAMOLE_VERSION=1.6.0
+
+RUN FREERDP_PLUGIN_DIR=$(pkg-config --variable=libdir freerdp3 2>/dev/null)/freerdp3 \
+    && echo "Building guacamole-server ${GUACAMOLE_VERSION} with FreeRDP plugin dir: ${FREERDP_PLUGIN_DIR}" \
+    && curl -fsSL \
+        "https://downloads.apache.org/guacamole/${GUACAMOLE_VERSION}/source/guacamole-server-${GUACAMOLE_VERSION}.tar.gz" \
+       | tar -xzf - \
+    && cd "guacamole-server-${GUACAMOLE_VERSION}" \
+    && autoreconf -fi \
+    && CPPFLAGS="-Wno-error=deprecated-declarations" \
+       ./configure \
+           --prefix=/usr \
+           --sysconfdir=/etc \
+           --with-freerdp-plugin-dir="${FREERDP_PLUGIN_DIR}" \
+    && make -j"$(nproc)" \
+    && make install \
+    && ldconfig \
+    && cd / && rm -rf "guacamole-server-${GUACAMOLE_VERSION}"
+
+# guacd log level is passed via -L flag; exposed as env var for docker-compose
+ENV GUACD_LOG_LEVEL=info
+
+EXPOSE 4822
+
+CMD sh -c "exec /usr/sbin/guacd -b 0.0.0.0 -f -L \"${GUACD_LOG_LEVEL}\""