feat: initial headless sync server implementation

Dockerfile

@@ -0,0 +1,20 @@
+FROM node:20-slim
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y \
+    curl \
+    git \
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Obsidian Headless CLI
+RUN npm install -g obsidian-headless
+
+# Create vault directory
+WORKDIR /vault
+
+# Copy entrypoint script
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]