perf: optimize node flight payload framing
Context:
- Build node flight script frames using fewer temporary arrays/objects.
- Keep output bytes identical while reducing framing overhead for large payloads.
Benchmark (micro scenario, 300 iterations, 30 warmup, parent-file swap):
- createInlinedDataNodeStream only median: 0.456ms -> 0.415ms (+9.07% faster)
- createInlinedDataNodeStream (utf8) median: 0.884ms -> 0.825ms (+6.73% faster)
- Node continueDynamicHTMLResume median: 0.657ms -> 0.571ms (+12.98% faster)
