enforce antislop in the quality gate

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

README.md

@@ -117,16 +117,17 @@ cargo run -- imported.agnd --import tasks.ics
 ## Development quality gate
 
 Compiler warnings are denied by project configuration. Before accepting any
-change, run the complete gate:
+change, install the pinned Antislop release and run the complete gate:
 
 ```sh
+cargo install antislop --version 0.3.0 --locked
 ./scripts/quality-gate.sh
 ```
 
 It requires clean `cargo fmt --check` output, runs Clippy across every target and
-feature with `-D warnings`, executes all tests, builds warning-free documentation,
-and produces the release binary. Any warning, formatting difference, test failure,
-or build failure stops the gate.
+feature with `-D warnings`, rejects Antislop findings, executes all tests, builds
+warning-free documentation, and produces the release binary. Any finding, warning,
+formatting difference, test failure, or build failure stops the gate.
 
 ## Essential keys