Function assertChainedRunKeyFits

src/commands/test.ts:555–570

* Chained `test create --run` / `test create --plan-from --run` derive the * trigger idempotency key as ` :run`. Validate that derived key * BEFORE the create POST so a near-limit user-supplied base key fails fast * (exit 5) instead of creating the test and THEN rejecting the 257+ char

(
  run: boolean | undefined,
  idempotencyKey: string | undefined,
)

 * `runCreate` / `runCreateFromPlan` when chaining into `runTestRun`.
 */
function assertChainedRunKeyFits(
  run: boolean | undefined,
  idempotencyKey: string | undefined,
): void {
  if (run !== true || idempotencyKey === undefined) return;
  const RUN_SUFFIX = ':run';
  if (idempotencyKey.length + RUN_SUFFIX.length > 256) {
    throw localValidationError(
      'idempotencyKey',
      `must be at most ${256 - RUN_SUFFIX.length} characters when used with --run ` +
        `(the chained trigger derives "<key>${RUN_SUFFIX}", which must stay within the 256-char limit)`,
      undefined,
      'flag',
    );
  }
}

/**
 * B3 / Fix 4: best-effort duplicate-name advisory shared by `runCreate`