[Bug]: Settings sections became a tree view, and it's harder to use with a screen reader than the list it replaced #30800

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Turn on NVDA and open Settings.
2. In browse mode, Down arrow through the settings sections.
3. Press H to jump between the section groups.
4. Tab from the settings search field into the sections, and keep pressing Tab.

Expected behavior

The settings sections work like they did before #25877, and like the Threads sidebar does again since #26690: a list of buttons I can read in browse mode, Tab through, and jump between with H.

I'm asking for the same direction that was approved in #26562 for the Threads sidebar:

• Remove the tree roles (role="tree", role="treeitem", aria-selected) and the single Tab stop, so every section is in the Tab order again.
• Make the nav's group headings (Agents, Code, Connections) real headings again, and label each group by its heading (aria-labelledby), so H works in browse mode and Tab still announces the group in focus mode.
• Keep F6, aria-current="page" on the open section, and Up/Down/Home/End as an extra.
• Sections stay buttons, and nothing changes visually.

Actual behavior

Since #25877 the settings sections are an ARIA tree with one Tab stop (SettingsSidebarNav.tsx and useSettingsSectionNavigation.ts):

• In browse mode, every line starts with "Settings sections tree view".
• Tab reaches the open section, then leaves the nav. To reach any other section I have to switch to focus mode and use the arrow keys.
• The nav's group headings (Agents, Code, Connections) are aria-hidden because a heading can't be a tree child, so H skips them and goes straight to the page's headings.

The tree doesn't give anything back here. Every section is at level 1, nothing expands, and Left and Right do nothing. It's a flat list of sections, so the reasoning in #26562 applies even more strongly.

The trade-off is the same as for the Threads sidebar: focus mode no longer announces position ("3 of 22"), and Tab stops on every section. F6 still jumps past the nav.

Impact

Minor bug or occasional failure

Version or commit

main @ 8b44f42

Environment

Windows 11, NVDA 2026.3, T3 Code desktop

Logs or stack traces

Screenshots, recordings, or supporting files

No response

Workaround

No response