enforce antislop in the quality gate

- Pin the required Antislop release and document installation
- Reject Antislop findings during quality checks

scripts/quality-gate.sh

@@ -8,6 +8,14 @@ cargo fmt --all -- --check
 # and automated Clippy runs have the same, visible contract.
 cargo clippy --all-targets --all-features -- -D warnings
 
+antislop_version=0.3.0
+if ! command -v antislop >/dev/null 2>&1 ||
+    [[ "$(antislop --version)" != "antislop ${antislop_version}" ]]; then
+    echo "antislop ${antislop_version} is required; install it with: cargo install antislop --version ${antislop_version} --locked" >&2
+    exit 1
+fi
+antislop .
+
 cargo test --all-targets --all-features
 RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --all-features
 cargo build --release --all-targets --all-features