fix(ci): add workspace root src/lib.rs, fix Docker build target

Dockerfile

@@ -9,12 +9,13 @@ RUN apt-get update && apt-get install -y \
     libssl-dev \
     && rm -rf /var/lib/apt/lists/*
 
-# Copy manifests
+# Copy manifests and source
 COPY Cargo.toml Cargo.lock ./
+RUN mkdir -p src && echo '// workspace root' > src/lib.rs
 COPY crates ./crates
 
 # Build release binary
-RUN cargo build --release --bin mem
+RUN cargo build --release -p mem-cli --bin mem
 
 # Runtime stage
 FROM debian:bookworm-slim

src/lib.rs

@@ -0,0 +1 @@
+// Workspace root - integration tests live in tests/