fix: split Dockerfile apt-get calls (match proven build pattern)

Use openssl passwd instead of chpasswd, split apt-get into two
separate calls matching the old Dockerfile that built successfully.

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

Dockerfile

@@ -5,22 +5,28 @@ FROM ubuntu:24.04
 
 ENV DEBIAN_FRONTEND=noninteractive
 
-# System + Python + tools (single layer)
+# Core: Python + git-lfs + huggingface_hub
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    ca-certificates curl wget git git-lfs \
-    python3 python3-pip python3-venv \
-    openssh-server nginx ttyd rsync zstd \
-    procps htop vim nano less tmux build-essential \
+    ca-certificates curl wget python3 python3-pip python3-venv git git-lfs \
     && pip3 install --no-cache-dir --break-system-packages huggingface_hub websockets \
     && git lfs install \
     && rm -rf /var/lib/apt/lists/*
 
+# Server: SSH + nginx + ttyd + tools
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    openssh-server openssh-client \
+    nginx \
+    ttyd \
+    procps htop vim nano less tmux \
+    build-essential rsync zstd \
+    && rm -rf /var/lib/apt/lists/*
+
 # Node.js 20 LTS (for Claude Code)
 RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
     && apt-get install -y nodejs \
     && rm -rf /var/lib/apt/lists/*
 
-# Claude Code
+# Claude Code (install globally so all users can access)
 RUN npm install -g @anthropic-ai/claude-code 2>/dev/null \
     || (curl -fsSL https://claude.ai/install.sh | bash && \
         cp /root/.local/bin/claude /usr/local/bin/claude 2>/dev/null || true)
@@ -28,23 +34,23 @@ RUN npm install -g @anthropic-ai/claude-code 2>/dev/null \
 # Snapshot base package list (to detect user-added packages later)
 RUN dpkg-query -W -f='${Package}\n' | sort > /etc/base-packages.list
 
-# SSH host keys
+# SSH: host keys + privilege separation directory
 RUN ssh-keygen -A && mkdir -p /run/sshd
 
-# User account
-RUN useradd -m -u 1000 -s /bin/bash user 2>/dev/null || true \
-    && echo "user:huggingrun" | chpasswd \
-    && echo "root:huggingrun" | chpasswd
-
+# User account (for SSH login); container runs as root for system persistence
+RUN useradd -m -u 1000 -s /bin/bash -p "$(openssl passwd -6 huggingrun)" user 2>/dev/null || true
+# Root password for SSH login as root
+RUN usermod -p "$(openssl passwd -6 huggingrun)" root
 RUN mkdir -p /data
 
-# v2: only 3 files
+# v2: only 3 files (entrypoint + nginx + ws-bridge)
 COPY entrypoint.py /entrypoint.py
 COPY nginx.conf /etc/nginx/nginx.conf
 COPY ws_ssh_bridge.py /ws_ssh_bridge.py
 
 ENV PERSIST_PATH=/data
 ENV PYTHONUNBUFFERED=1
-EXPOSE 7860
 
+# Run as root (needed for: apt install persistence, bind mounts, sshd)
+EXPOSE 7860
 ENTRYPOINT ["python3", "-u", "/entrypoint.py"]