test(web): enforce one-pass smoke execution

tools/web/run-wbv2-feature-smoke-plan.mjs

@@ -42,6 +42,14 @@ if (!execute) {
   process.exit(0);
 }
 
+if (fs.existsSync(reportPath)) {
+  const previous = JSON.parse(fs.readFileSync(reportPath, "utf8"));
+  if (previous.planId === plan.planId && Array.isArray(previous.cases) && previous.cases.some((item) => Number(item.attempts ?? 0) > 0)) {
+    process.stderr.write(`feature-smoke-once-only: plan ${plan.planId} already has recorded attempts; create a new focused-fix batch instead of rerunning\n`);
+    process.exit(2);
+  }
+}
+
 const startedAt = new Date().toISOString();
 const smokeReport = {
   schemaVersion: 1,