Settings: independently scroll the section sidebar / 设置左侧配置列表支持独立滚动

[chenmzh]

问题 / Problem

DSH Web 设置弹窗左侧的配置分区列表没有独立的纵向滚动区域。安装较多插件、窗口较矮或浏览器放大时，末尾配置入口可能被弹窗裁切，用户无法通过鼠标滚轮访问它们。

The Settings dialog's section navigation needs its own vertical scroll area. With many plugin-contributed sections, a short viewport, or browser zoom, the trailing settings entries can be clipped and cannot be reached with the mouse wheel.

复现 / Reproduction

1. Register enough settings.section entries to exceed the dialog height.
2. Open Settings and reduce the viewport height (for example, to 400 px).
3. Put the pointer over the left section list and scroll down.

Observed in a local source deployment of 0.1.2-rc.1, based on commit 4459421c37be9ab59665f723c89d019669ce1658. In packages/client/ui-settings-general/src/client/SettingsRoot.module.css, .panel has a bounded height and overflow: hidden, while only the right .options pane has overflow-y: auto; .navList has no scroll container.

建议 / Proposal

• Keep the Settings title fixed above the navigation list.
• Give the list flex: 1, min-height: 0, and overflow-y: auto within the existing bounded navigation column.
• Keep navigation rows from shrinking (flex: none) and add bottom padding so the final entry is comfortably reachable.
• Contain vertical overscroll and reuse the existing shared scrollbar theme.
• Keep left navigation and right content scrolling independent; preserve keyboard access to the last entry.

左栏应能通过滚轮、触控板和键盘访问全部配置项，同时不影响右侧内容区滚动。

本地修复与验证 / Local fix and validation

A local CSS fix is implemented and the settings client bundle builds successfully. An isolated Chromium check using the actual stylesheet reproduced clipping before the fix and passed after it:

• 30 sections at 400 px and 900 px viewport heights: wheel scrolling reaches the final entry.
• The title stays fixed, rows stay 40 px high, and the right pane does not scroll along with the navigation.
• Keyboard Tab reaches the last entry; a short three-entry list does not acquire unnecessary scrolling.
• pnpm run test:gui: 282 files passed; 3,903 tests passed, 1 skipped.

This is a local fix and a feature request for upstream inclusion; no upstream PR is included here. Related navigation decluttering discussion: #5756. Independent scrolling remains useful regardless of how sections are grouped.