static void RunStabilityEditorChecks() {
    SpriteEntry sprite{};
    sprite.textureId = 13;
    Check(GetSpriteEntityType(sprite) == ENTITY_ARCHETYPE_GUARD, "zero flags retain legacy guard fallback");
    sprite.flags = 0x06026400;
    Check(GetSpriteEntityType(sprite) == ENTITY_ARCHETYPE_PROP, "explicit Prop matches ASM despite guard texture");
    sprite.textureId = 11;
    sprite.flags = 0;
    Check(GetSpriteEntityType(sprite) == ENTITY_ARCHETYPE_BARREL, "zero flags retain new legacy barrel fallback");
    sprite.flags = 0x06026400;
    Check(GetSpriteEntityType(sprite) == ENTITY_ARCHETYPE_PROP, "explicit Prop overrides barrel artwork");
    for (int health : {1, 100, 255, 256, 300, 500}) {
        SetSpriteEntityData(sprite, ENTITY_ARCHETYPE_GUARD, health, 2, 6);
        Check(GetSpriteHealth(sprite) == (health > 255 ? 255 : health), "health setter clamps before byte packing");
    }

    const auto root = fs::absolute("code fixture");
    fs::create_directories(root / "include");
    const auto first = root / g_ProjectCodeFiles[0].relativePath;
    const auto second = root / g_ProjectCodeFiles[1].relativePath;
    { std::ofstream out(first); out << "original"; }
    { std::ofstream out(second); out << "second"; }
    CodeEditorState code;
    code.LoadFile(0, root.string());
    Check(std::string(code.textBuffer.data()) == "original", "IDE opens actual source file");
    strcpy_s(code.textBuffer.data(), code.textBuffer.size(), "unsaved source");
    code.isModified = true;
    HANDLE locked = CreateFileA(first.string().c_str(), GENERIC_READ, FILE_SHARE_READ,
        nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
    Check(locked != INVALID_HANDLE_VALUE, "IDE failure fixture locks destination against replacement");
    Check(!code.SaveFile(root.string()) && code.isModified &&
        Bytes(first) == std::vector<uint8_t>({'o','r','i','g','i','n','a','l'}),
        "failed IDE replacement preserves disk and modified buffer");
    code.LoadFile(1, root.string());
    Check(code.currentFile == 0 && code.isModified && std::string(code.textBuffer.data()) == "unsaved source",
        "IDE refuses file switch after failed autosave");
    code.StartBuild(root.string());
    Check(!code.isBuilding && code.isModified, "IDE refuses build after failed save");
    CloseHandle(locked);
    Check(code.SaveFile(root.string()) && !code.isModified &&
        Bytes(first) == std::vector<uint8_t>({'u','n','s','a','v','e','d',' ','s','o','u','r','c','e'}),
        "IDE publishes complete source atomically");
    code.LoadFile(1, root.string());
    Check(code.currentFile == 1 && std::string(code.textBuffer.data()) == "second", "IDE switches after successful save");
    fs::remove(first);
    code.LoadFile(0, root.string());
    Check(code.currentFile == 1 && std::string(code.textBuffer.data()) == "second", "failed IDE load preserves current document");
    Check(std::distance(fs::directory_iterator(root / "include"), fs::directory_iterator{}) == 1,
        "failed IDE saves leave no temporary source files");

    { std::ofstream out(root / "build.bat");
      out << "@echo off\nfor /L %%i in (1,1,4000) do echo compiler-output-%%i\nexit /b 7\n"; }
    g_CodeEditor.LoadFile(1, root.string());
    g_CodeEditor.StartBuild(root.string());
    EditorApp hidden;
    hidden.showCodeEditorModal = false;
    const auto deadline = GetTickCount64() + 10000;
    while (g_CodeEditor.isBuilding && GetTickCount64() < deadline) {
        hidden.RenderCodeEditorWindow();
        if (g_CodeEditor.hBuildProcess) WaitForSingleObject(g_CodeEditor.hBuildProcess, 1);
    }
    const bool finished = !g_CodeEditor.isBuilding;
    if (!finished && g_CodeEditor.hBuildProcess) {
        TerminateProcess(g_CodeEditor.hBuildProcess, 99);
        WaitForSingleObject(g_CodeEditor.hBuildProcess, 1000);
        g_CodeEditor.PollBuild();
    }
    Check(finished && g_CodeEditor.buildExitCode == 7 &&
        g_CodeEditor.buildLog.find("compiler-output-4000") != std::string::npos,
        "hidden IDE drains output larger than pipe capacity and retains exit code");
}