fix: revert to single-stage Dockerfile for stability

The multi-stage build caused HF Space routing issues — the container
showed RUNNING but traffic wasn't forwarded to port 7860 (404).
Reverting to proven single-stage build while we investigate.

Dockerfile

@@ -1,9 +1,6 @@
-# ============================================================
-# Stage 1: Builder — clone, build, patch (discarded after)
-# ============================================================
-FROM python:3.12-slim AS builder
+FROM python:3.12-slim
 
-# Build tools needed for node-pty native compilation
+# System deps (add build tools for node-pty native compilation)
 RUN apt-get update && apt-get install -y --no-install-recommends \
     git curl gnupg2 fontconfig make g++ python3 \
     && rm -rf /var/lib/apt/lists/*
@@ -20,29 +17,41 @@ RUN pip install --quiet --upgrade pip && \
     pip install --quiet psutil networkx && \
     pip install --quiet -e "/app/hermes-agent[feishu,mcp,cron,pty]" 2>&1 | tail -10
 
-# All patches (non-fatal — won't break build if upstream changed)
+# Patch: add document file extensions to auto-detection for native delivery
 COPY scripts/patch_file_delivery.py /tmp/patch_file_delivery.py
 RUN python3 /tmp/patch_file_delivery.py; rm -f /tmp/patch_file_delivery.py
 
+# Patch: Feishu media support in send_message_tool + anti-hallucination prompts
 COPY patches/hermes-agent/agent/prompt_builder.py /app/hermes-agent/agent/prompt_builder.py
 COPY patches/hermes-agent/tools/send_message_tool.py /app/hermes-agent/tools/send_message_tool.py
 
+# Patch: Auto-inject MEDIA: tags from write_file tool calls
 COPY scripts/patch_auto_media.py /tmp/patch_auto_media.py
 RUN python3 /tmp/patch_auto_media.py; rm -f /tmp/patch_auto_media.py
 
+# Patch: Auto-resolve relative media paths to absolute paths
 COPY scripts/patch_resolve_media_paths.py /tmp/patch_resolve_media_paths.py
 RUN python3 /tmp/patch_resolve_media_paths.py; rm -f /tmp/patch_resolve_media_paths.py
 
-# Install Node.js 23 for web-ui build
+# Install Node.js 23
 RUN ARCH=$(dpkg --print-architecture) \
     && if [ "$ARCH" = "amd64" ]; then NODE_ARCH="x64"; else NODE_ARCH="$ARCH"; fi \
+    && echo "Installing Node.js v23 for ${NODE_ARCH}" \
     && curl -fsSL "https://nodejs.org/dist/v23.11.0/node-v23.11.0-linux-${NODE_ARCH}.tar.gz" \
        -o /tmp/node.tar.gz \
     && tar -xzf /tmp/node.tar.gz -C /usr/local --strip-components=1 \
     && rm -f /tmp/node.tar.gz \
     && node --version && npm --version
 
-# Build hermes-web-ui
+# Chinese font (Noto Sans SC Regular + Bold)
+RUN mkdir -p /usr/share/fonts/truetype/noto && \
+    curl -sL "https://github.com/googlefonts/noto-cjk/raw/main/Sans/SubsetOTF/SC/NotoSansSC-Regular.otf" \
+    -o /usr/share/fonts/truetype/noto/NotoSansSC-Regular.otf && \
+    curl -sL "https://github.com/googlefonts/noto-cjk/raw/main/Sans/SubsetOTF/SC/NotoSansSC-Bold.otf" \
+    -o /usr/share/fonts/truetype/noto/NotoSansSC-Bold.otf && \
+    fc-cache -f
+
+# Build hermes-web-ui (keep node_modules for runtime deps)
 RUN git clone --depth 1 https://github.com/EKKOLearnAI/hermes-web-ui.git /tmp/hermes-web-ui && \
     cd /tmp/hermes-web-ui && \
     npm install --ignore-scripts 2>&1 | tail -5 && \
@@ -57,45 +66,6 @@ RUN git clone --depth 1 https://github.com/EKKOLearnAI/hermes-web-ui.git /tmp/he
     rm -rf /tmp/hermes-web-ui && \
     echo "hermes-web-ui build done"
 
-
-# ============================================================
-# Stage 2: Runtime — minimal image with only what's needed
-# ============================================================
-FROM python:3.12-slim
-
-# Runtime deps only (no build tools)
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    curl fontconfig \
-    && rm -rf /var/lib/apt/lists/*
-
-WORKDIR /app
-
-# Copy built venv + patched hermes-agent from builder
-COPY --from=builder /app/venv /app/venv
-COPY --from=builder /app/hermes-agent /app/hermes-agent
-
-ENV PATH="/app/venv/bin:$PATH"
-
-# Copy Node.js runtime from builder (needed for webui-server BFF)
-COPY --from=builder /usr/local/bin/node /usr/local/bin/node
-COPY --from=builder /usr/local/lib/node_modules /usr/local/lib/node_modules
-# Symlink npm/npx if they don't exist
-RUN ln -sf /usr/local/lib/node_modules/npm/bin/npm-cli.js /usr/local/bin/npm 2>/dev/null; \
-    ln -sf /usr/local/lib/node_modules/npm/bin/npx-cli.js /usr/local/bin/npx 2>/dev/null; \
-    true
-
-# Copy built web-ui from builder
-COPY --from=builder /app/webui-server /app/webui-server
-COPY --from=builder /app/webui-client /app/webui-client
-
-# Chinese fonts (download in runtime stage — only ~16MB)
-RUN mkdir -p /usr/share/fonts/truetype/noto && \
-    curl -sL "https://github.com/googlefonts/noto-cjk/raw/main/Sans/SubsetOTF/SC/NotoSansSC-Regular.otf" \
-    -o /usr/share/fonts/truetype/noto/NotoSansSC-Regular.otf && \
-    curl -sL "https://github.com/googlefonts/noto-cjk/raw/main/Sans/SubsetOTF/SC/NotoSansSC-Bold.otf" \
-    -o /usr/share/fonts/truetype/noto/NotoSansSC-Bold.otf && \
-    fc-cache -f
-
 # Create hermes home
 RUN mkdir -p /root/.hermes/plugins/image_gen/pollinations