Android tablets: float the Chats / PRs switch inside the sidebar instead of a separate rail

[SamarpitSantoki]

Problem

On Android tablets, the split layout puts the Chats / PRs switch in its own navigation rail: an 80dp column to the left of the sidebar. The rail holds only two tabs, centered vertically, so most of the column is empty space. It takes width from the sidebar and detail panes, and the tabs sit far from the other sidebar controls (New thread and the filter, which float at the bottom of the sidebar).

Proposal

Drop the rail on tablets and float a compact Chats / PRs switch inside the sidebar, at the bottom left. It mirrors the New thread FAB and filter button at the bottom right: same height, corner shape, and elevation, with the selected tab shown by a tonal indicator.

• Landscape: the switch sits on the New thread row.
• Narrow sidebars (portrait): when the switch and New thread would collide, the switch rises to the filter row.
• Phones are unchanged and keep the Material bottom navigation bar.
• iOS is unchanged.

Selecting a tab behaves exactly as the rail did today: it switches the sidebar list and closes the open detail.

Screenshots

Before: Xiaomi Pad 6. After: Pixel Tablet emulator (Android 16). Thread and PR titles are blurred.

Before: landscape	After: landscape (Chats)	After: landscape (PRs)

Before: portrait	After: portrait (Chats)	After: portrait (PRs)

Question for maintainers

Is this a direction you want for Android tablets? I have a working implementation in draft PR #18686, which stays in draft until the direction is approved here. Happy to change placement or styling, or to drop it.

[colonelpanic8]

+1 on this direction. On my tablet the rail is mostly empty space, and the Chats / PRs switch ends up far from every other sidebar control.

A related ask: a setting to hide the PRs tab entirely, for people who don't review PRs on mobile. With it off, there's no switch at all and Chats gets the full width. That would cover phones and iOS too, not just Android tablets. Happy to put up a PR for it if maintainers are open to it.