优化原生结果编码传输与浏览器缓存，记录八路性能基线

原生结果series通过字节索引直传，C端使用Ryu精确回读编码和64 KiB批量写出；网页采用Float64缓存和CSV工作线程，减少结果处理与保存等待。

补充八路AME曲线核查、全流程分阶段计时、独立编码基准和复现工具，固定后续优化采用修正八路及rtol=1e-8。C写出1.1808→0.1638 s，点击到可查看8.0100→6.9756 s。

验证：最终10项编码专项、29项相关后端回归通过；8份原生结果逐位一致，16次网页结果/CSV/刷新恢复通过。前端构建及缓存/CSV专项在本轮结果处理工作中通过。环境、原始大结果与临时构建不纳入Git。

app/main.py

@@ -23,6 +23,7 @@ from fastapi.responses import FileResponse, HTMLResponse, StreamingResponse
 from pydantic import BaseModel, ConfigDict, Field, ValidationError
 
 from app.simulation.performance import performance_span, profile_phase, profile_run
+from app.simulation.native_codegen.transport import NativeSeriesJson, serialize_result_parts
 from app.simulation.config import SolverActivityTracker
 from app.system_xml import (
     SystemXmlDocument,
@@ -652,7 +653,7 @@ async def simulate_system_xml_stream(request: Request) -> StreamingResponse:
     simulation_id = request.headers.get("x-simulation-id") or uuid4().hex
     task = _register_simulation_task(simulation_id)
     return StreamingResponse(
-        simulation_event_stream(await request.body(), task=task),
+        simulation_event_stream(await request.body(), task=task, raw_series=True),
         media_type="application/x-ndjson",
         headers={
             "Cache-Control": "no-cache, no-transform",
@@ -679,13 +680,17 @@ def cancel_system_xml_simulation(
     }
 
 
-@app.get("/api/system-xml/simulations/{simulation_id}")
-def get_system_xml_simulation(simulation_id: str) -> dict[str, object]:
+@app.get("/api/system-xml/simulations/{simulation_id}", response_model=None)
+def get_system_xml_simulation(simulation_id: str) -> dict[str, object] | Response:
     with SIMULATION_TASKS_LOCK:
         task = SIMULATION_TASKS.get(simulation_id)
     if task is None:
         raise HTTPException(status_code=404, detail="Simulation task was not found.")
-    return _simulation_task_snapshot(task)
+    snapshot = _simulation_task_snapshot(task)
+    result = snapshot.get("result")
+    if isinstance(result, dict) and isinstance(result.get("series"), NativeSeriesJson):
+        return StreamingResponse(iter(serialize_result_parts(snapshot)), media_type="application/json")
+    return snapshot
 
 
 def run_system_xml_simulation(
@@ -693,6 +698,7 @@ def run_system_xml_simulation(
     progress_callback: SimulationProgressEmitter | None = None,
     cancel_check: Callable[[], bool] | None = None,
     activity_tracker: SolverActivityTracker | None = None,
+    *, raw_series: bool = False,
 ) -> dict[str, object]:
     with profile_run() as trace:
         result = _run_system_xml_simulation_profiled(
@@ -700,6 +706,7 @@ def run_system_xml_simulation(
             progress_callback,
             cancel_check,
             activity_tracker,
+            raw_series=raw_series,
         )
 
     performance = trace.snapshot()
@@ -715,6 +722,7 @@ def _run_system_xml_simulation_profiled(
     progress_callback: SimulationProgressEmitter | None = None,
     cancel_check: Callable[[], bool] | None = None,
     activity_tracker: SolverActivityTracker | None = None,
+    *, raw_series: bool = False,
 ) -> dict[str, object]:
     from app.simulation.backends import simulate_network
     from app.simulation.results import SimulationPreparationError
@@ -762,6 +770,7 @@ def _run_system_xml_simulation_profiled(
             progress_callback=report_system_progress,
             cancel_check=cancel_check,
             activity_tracker=activity_tracker,
+            raw_series=raw_series,
         )
     except SimulationPreparationError as exc:
         raise HTTPException(
@@ -799,7 +808,7 @@ def _run_system_xml_simulation_profiled(
             "validation": report.as_dict(),
             "simulation": document.as_model_data()["simulation"],
             "model": network.as_interface_dict(),
-            **result.as_dict(),
+            **result.as_dict(raw_series=raw_series),
         }
 
 
@@ -807,7 +816,8 @@ def simulation_event_stream(
     xml_bytes: bytes,
     *,
     task: SimulationTaskRecord | None = None,
-) -> Iterator[str]:
+    raw_series: bool = False,
+) -> Iterator[str | bytes]:
     events: queue.Queue[dict[str, object] | object] = queue.Queue()
     finished = object()
     latest_progress = 0
@@ -857,6 +867,7 @@ def simulation_event_stream(
                 emit_progress,
                 task.cancel_event.is_set if task is not None else None,
                 activity_tracker,
+                **({"raw_series": True} if raw_series else {}),
             )
             if task is not None:
                 result = _mark_simulation_task_result(task, result)
@@ -958,7 +969,11 @@ def simulation_event_stream(
                 continue
             if event is finished:
                 break
-            yield json.dumps(event, ensure_ascii=False, separators=(",", ":")) + "\n"
+            if raw_series and isinstance(event, dict) and event.get("event") == "result":
+                yield from serialize_result_parts(event)
+                yield b"\n"
+            else:
+                yield json.dumps(event, ensure_ascii=False, separators=(",", ":")) + "\n"
     finally:
         if task is not None:
             _request_simulation_task_cancel(task, "stalled")