Phone PR surfaces: row-menu rows below 44pt and clipped diff header counts #662

Two touch-target and layout defects on the phone example at 393pt (A4 design pass): (1) the Pull requests row menu's rows are about 30pt high; the Track A design asks for 44px rows on touch like the thread menu; (2) in the phone diff header the +/− counts are clipped, and an untracked file showed an old-line number 1 against a blank new line 4. Screenshots: tmp/screenshots/design-a4/phone-light-pull-requests-row-menu.png and phone-light-panels-diff.png in the maintainer's checkout.

Also (A5 design pass, 2026-10-09)

• The PR detail and row ⋯ menus render no icons although the Track A design lists one per item, and the accessibility tree exposes every menu item unnamed, on desktop and phone.
• On the phone PR page the chip row clips ("Conflicts with c…") and the layer selector sits off-screen with no scroll cue.

Also (A6 design pass, 2026-10-09)

• The PR page's layer selector trigger has no accessible name; unlinked layers are named "chore(deps): bump android-actions/setup-android from 3 to 4 #415 " (trailing space) and no item names its state; the phone stack pill has no press action in the accessibility tree.
• "Layer N of M" truncates first on desktop rows and disappears on most phone rows; desktop line 2 shows an empty "· ·" where the author gave way; the phone layer sheet keeps a fixed 340pt list width; the phone chip row clips "Layer 5 of 6" with no cue.