Fix Dockerfile: use python:3.12-slim for pre-built wheels

pymupdf and other native deps need compilation on Alpine.
Switch to Debian-based python:3.12-slim which has pre-built
wheels available, avoiding the need for gcc/build-essential.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -22,18 +22,23 @@ COPY web-ui/ ./
 ENV NEXT_TELEMETRY_DISABLED=1
 RUN npm run build
 
-# ── Stage 3: Install Python deps ─────────────────────────────
-FROM python:3.12-alpine AS pydeps
+# ── Stage 3: Install Python deps (use slim for pre-built wheels) ──
+FROM python:3.12-slim AS pydeps
 WORKDIR /opt/api
 COPY mcp-server/ ./mcp-server/
 RUN pip install --no-cache-dir ./mcp-server
 
 # ── Stage 4: Runner ───────────────────────────────────────────
-FROM python:3.12-alpine AS runner
+FROM python:3.12-slim AS runner
 WORKDIR /app
 
-# Install Node.js (needed for Next.js standalone server)
-RUN apk add --no-cache nodejs
+# Install Node.js 20.x
+RUN apt-get update && apt-get install -y --no-install-recommends \
+      curl ca-certificates \
+ && curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
+ && apt-get install -y --no-install-recommends nodejs \
+ && apt-get purge -y curl \
+ && rm -rf /var/lib/apt/lists/*
 
 ENV NODE_ENV=production
 ENV NEXT_TELEMETRY_DISABLED=1