Serialize cost toolchain executable fixture checks

Author: a19q3

scripts/cellscript_gate.sh

@@ -638,7 +638,8 @@ run_dev_gate() {
 
 prepare_cost_evidence() {
     printf '{"status":"not-generated","reason":"cost corpus has not completed"}\n' >"$CELLSCRIPT_COST_CORPUS_REPORT"
-    run cargo test --locked -p cellscript --test cost_toolchain
+    # Keep temporary executable fixtures and process-launch checks serialized.
+    run cargo test --locked -p cellscript --test cost_toolchain -- --test-threads=1
 }
 
 check_cost_evidence() {

tests/fixtures/business_corpus.json

@@ -1010,7 +1010,7 @@
       ]
     }
   ],
-  "inventory_sha256": "0xffdccc43ac2235f84f258c82d8a6e0616a99fb6bf7e7b3bceac1cc0ff4a139d4",
+  "inventory_sha256": "0x57c1eb0bc66a417cef88fd26224b3776806de8f9a14fba10788ca80173fa07f8",
   "release_requirements": {
     "backend": "passed",
     "ci": "passed",