tests: Use a fixed seed for mutation trace refinement runs

Pin the Quint runner seed so generated mutation traces are reproducible across runs.

Co-authored-by: SCE <sce@crocoder.dev>

Author: davidabram

cli/src/services/mutation_trace/mbt/tests.rs

@@ -169,7 +169,8 @@ fn mutation_cursor_guarded_recover_invokes_real_recover() -> impl Driver {
 #[quint_run(
     spec = "../spec/mutation_cursor.qnt",
     max_samples = 500,
-    max_steps = 30
+    max_steps = 30,
+    seed = "0xbd646ab9"
 )]
 fn mutation_cursor_generated_traces_refine_rust_protocol() -> impl Driver {
     MutationCursorDriver::default()