Fix asap-planner-rs Dockerfile: add dummy bench stub for simple_store_bench

Same fix as asap-query-engine/Dockerfile — the workspace Cargo.toml for
asap-query-engine declares [[bench]] simple_store_bench, so Cargo requires
the file to exist even during dependency-only builds.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: zzylol

asap-planner-rs/Dockerfile

@@ -13,6 +13,7 @@ COPY asap-planner-rs/Cargo.toml ./asap-planner-rs/
 
 # Create dummy source files so Cargo can resolve all workspace members
 RUN mkdir -p asap-query-engine/src && echo "fn main() {}" > asap-query-engine/src/main.rs && \
+    mkdir -p asap-query-engine/benches && echo "fn main() {}" > asap-query-engine/benches/simple_store_bench.rs && \
     mkdir -p asap-planner-rs/src && echo "fn main() {}" > asap-planner-rs/src/main.rs && \
     echo "pub fn placeholder() {}" >> asap-planner-rs/src/lib.rs