Deprecate Alpine-based Dockerfile to prevent glibc compatibility issues

Changes:
- Renamed Dockerfile.simple → Dockerfile.simple.DEPRECATED
- Added prominent warning about Alpine/musl libc incompatibility
- Updated Makefile docker-agent target to use Dockerfile.ubuntu
- Added production deployment notes in Makefile
- Updated docker-compose.yml with LightRAG environment variables

Reason:
The chorus-agent binary built with 'make build-agent' is linked against
glibc and cannot run on Alpine's musl libc. This causes the runtime error:
"exec /app/chorus-agent: no such file or directory"

Production deployments MUST use Dockerfile.ubuntu for glibc compatibility.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Dockerfile.simple.DEPRECATED

@@ -0,0 +1,60 @@
+# ⚠️ DEPRECATED: DO NOT USE THIS DOCKERFILE ⚠️
+#
+# This Alpine-based Dockerfile is INCOMPATIBLE with the chorus-agent binary
+# built by 'make build-agent'. The binary is compiled with glibc dependencies
+# and will NOT run on Alpine's musl libc.
+#
+# ERROR when used: "exec /app/chorus-agent: no such file or directory"
+#
+# ✅ USE Dockerfile.ubuntu INSTEAD
+#
+# This file is kept for reference only and should not be used for builds.
+# Last failed: 2025-10-01
+# Reason: Alpine musl libc incompatibility with glibc-linked binary
+#
+# -------------------------------------------------------------------
+
+# CHORUS - Simple Docker image using pre-built binary
+FROM alpine:3.18
+
+# Install runtime dependencies
+RUN apk --no-cache add \
+    ca-certificates \
+    tzdata \
+    curl
+
+# Create non-root user for security
+RUN addgroup -g 1000 chorus && \
+    adduser -u 1000 -G chorus -s /bin/sh -D chorus
+
+# Create application directories
+RUN mkdir -p /app/data && \
+    chown -R chorus:chorus /app
+
+# Copy pre-built binary from build directory (ensure it exists and is the correct one)
+COPY build/chorus-agent /app/chorus-agent
+RUN chmod +x /app/chorus-agent && chown chorus:chorus /app/chorus-agent
+
+# Switch to non-root user
+USER chorus
+WORKDIR /app
+
+# Note: Using correct chorus-agent binary built with 'make build-agent'
+
+# Expose ports
+EXPOSE 8080 8081 9000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD curl -f http://localhost:8081/health || exit 1
+
+# Set default environment variables
+ENV LOG_LEVEL=info \
+    LOG_FORMAT=structured \
+    CHORUS_BIND_ADDRESS=0.0.0.0 \
+    CHORUS_API_PORT=8080 \
+    CHORUS_HEALTH_PORT=8081 \
+    CHORUS_P2P_PORT=9000
+
+# Start CHORUS
+ENTRYPOINT ["/app/chorus-agent"]