fix(qa): reject duplicate sqlite bench controls

scripts/bench-sqlite-state.ts

@@ -134,12 +134,17 @@ function hasFlag(flag: string, argv = process.argv.slice(2)): boolean {
 }
 
 function validateArgs(argv: string[]): void {
+  const seenValueFlags = new Set<string>();
   for (let index = 0; index < argv.length; index += 1) {
     const arg = argv[index] ?? "";
     if (BOOLEAN_FLAGS.has(arg)) {
       continue;
     }
     if (VALUE_FLAGS.has(arg)) {
+      if (seenValueFlags.has(arg)) {
+        throw new CliUsageError(`${arg} was provided more than once`);
+      }
+      seenValueFlags.add(arg);
       const value = argv[index + 1];
       if (!value || value.startsWith("-")) {
         throw new CliUsageError(`${arg} requires a value`);

test/scripts/bench-sqlite-state.test.ts

@@ -47,4 +47,12 @@ describe("scripts/bench-sqlite-state", () => {
       'error: --profile must be one of smoke, default, large; got "huge"',
     );
   });
+
+  it("rejects duplicate single-value controls before seeding benchmark databases", () => {
+    const result = runBench(["--profile", "smoke", "--profile", "large"]);
+
+    expect(result.status).toBe(2);
+    expect(result.stdout).toBe("");
+    expect(result.stderr.trim()).toBe("error: --profile was provided more than once");
+  });
 });