[Bug] memoryPressurePercent 使用 system-wide 计算，与 shortMemoryString 的 RSS 口径不一致

[ShadyUnderLight]

问题描述

shortMemoryString 用的是 memoryUsedBytes（RSS，来自 vm_statistics64 的 active + inactive + wired + compressor），但 memoryPressurePercent 显示的是 system-wide memory pressure 百分比。两者在 UI 中同时出现，但含义不同：

• shortMemoryString：用户进程视角的"已用内存"
• memoryPressurePercent：系统视角的"内存压力"

用户看到"已用 8G / 压力 95%"会很困惑。

预期结果

内存指标口径一致，或明确区分 system pressure 和 process RSS。

建议方案

将 memoryUsedBytes 改名为 systemMemoryUsedBytes 并在 SystemSummary 中加注释说明计算方式。shortMemoryString 显示的数和 memoryPressurePercent 是不同维度，应在 UI 上用不同标签区分。

[ShadyUnderLight]

Thanks for reporting this. This issue has already been addressed by the work in #13 / PR #24, which renamed `memoryUsedBytes` to `systemMemoryUsedBytes` with a clear comment documenting the active+inactive+wired+compressor calculation, added `appMemoryUsedBytes` for per-process RSS, and updated the UI label to `RAM (System-wide)` / `内存 (系统级)` so the two metrics are now clearly distinguished. Closing as already fixed.