feat(x): add headless server runner and Dockerfile for agent core

apps/x/Dockerfile

@@ -0,0 +1,52 @@
+FROM node:22-slim
+
+# Install system dependencies if needed (e.g. for native modules)
+RUN apt-get update && apt-get install -y \
+    python3 \
+    make \
+    g++ \
+    && rm -rf /var/lib/apt/lists/*
+
+# Enable pnpm
+RUN corepack enable
+
+WORKDIR /app
+
+# Copy workspace config
+COPY pnpm-lock.yaml pnpm-workspace.yaml package.json ./
+
+# Copy packages
+COPY apps/server ./apps/server
+COPY packages/core ./packages/core
+COPY packages/shared ./packages/shared
+# Note: we skip apps/main, apps/renderer, apps/preload as they are Electron-specific
+
+# Install dependencies (skipping Electron devDeps if possible, but they are in root)
+# We might need to ignore scripts or optional deps
+RUN pnpm install --frozen-lockfile
+
+# Build dependencies in order
+WORKDIR /app/packages/shared
+RUN npm run build
+
+WORKDIR /app/packages/core
+RUN npm run build
+
+WORKDIR /app/apps/server
+RUN npm run build
+
+WORKDIR /app
+
+# Set environment to production
+ENV NODE_ENV=production
+
+# The app uses ~/.rowboat for storage by default.
+# In Docker, we should probably mount a volume or set HOME.
+# Let's verify if we need to override the path via env var, but the code hardcodes path.join(homedir(), ".rowboat")
+# So setting HOME=/data should work, provided we create the dir.
+ENV HOME=/data
+RUN mkdir -p /data/.rowboat
+
+VOLUME /data/.rowboat
+
+CMD ["node", "apps/server/dist/main.js"]