前端进度条性能优化、仿真结束后后处理优化；后端C代码生成流程优化：先识别来源，再按照已知未知量需求排序，最后局部求解

frontend/tests/e2e/native-result.spec.ts

@@ -32,7 +32,12 @@ for (const diagnosticsMode of ["native", "legacy-native", "python"] as const) {
     } else {
       await expect(consolePanel).not.toContainText("最大方程残差");
     }
-    const saved = await page.evaluate(() => JSON.parse(sessionStorage.getItem("system-simulation-flow:latest-result") ?? "null"));
+    await expect.poll(() => page.evaluate(() => JSON.parse(sessionStorage.getItem("system-simulation-flow:latest-result") ?? "null")?.storage)).toBe("indexeddb");
+    const saved = await page.evaluate(async () => {
+      // @ts-expect-error Vite serves the persistence module in the test browser.
+      const { loadStoredResultSnapshot } = await import("/src/resultPersistence.ts");
+      return loadStoredResultSnapshot();
+    });
     expect(saved.result.diagnostics.sampleCount).toBe(3);
     expect(saved.result.series).toEqual(resultSnapshot.result.series);
     await page.reload();