With a selection, earlier breadcrumbs paint over the separator and the folder title #404

Where: web/src/styles/app.css:671-673.

What happens: While a selection lasts, every crumb gets min-width: 0 (.toolbar:has(.selection-bar) .breadcrumbs > *). Only the current crumb also gets overflow: hidden; text-overflow: ellipsis. The earlier crumbs shrink below their text and their text overflows visibly. Measured at 1280x800, de-du, in /home/Projekte with one row ticked: the "Mein Speicher" link box is 65 px wide and its text 90 px (scrollWidth 90 > clientWidth 65). On screen it reads "Mein Speiche/Proj..." with the letters running through the "/". English in /home/Projekte/Steuer 2026 does the same: "My storage" is 70 px of text in a 60 px box, "Projekte" 51 in 44.

Expected: Crumbs never overlap. An earlier crumb that has to give way is cut with its own ellipsis. The current crumb keeps at least 8rem and is cut with an ellipsis (DESIGN.md, "Tags and smart folders").

Fix: Under .toolbar:has(.selection-bar) .breadcrumbs, give every crumb link overflow: hidden; text-overflow: ellipsis; white-space: nowrap. Let the earlier crumbs shrink first: a high flex-shrink on them, and flex-shrink: 0 with min-width: 8rem on [aria-current=page]. Keep .sep at flex: none.

Test (Playwright, e2e/selection-bar.spec.ts, desktop): Use de-du at 1280x800 in /home/<dir>/<sub> with one row ticked. For every .breadcrumbs a, assert either scrollWidth <= clientWidth, or computed overflow: hidden together with text-overflow: ellipsis. Also assert that the bounding boxes of neighbouring crumb and separator elements do not intersect. Fails today.

Found by the automatic review round (claude-opus-5-5, b739414); per CLAUDE.md the fix starts with a failing behaviour test.