Settings at tablet widths: cards clip under the expanded

Found while verifying Task 7141 on the live stack (600–700px viewport, sidebar expanded). 1. Settings at 600px: the knob cards are wider than the content column, so the unit ("seconds", "attempts") and the whole Default column are clipped at the right edge with no scroll. Let the knob grid drop the Default column (or stack it under the field) below the compact band's width, as it does on a phone. 2. Settings at 600–760px: the search, Category and Discard/Save take two or three lines while something is unsaved. Consider collapsing the app sidebar automatically below ~760px, so the compact band has room for one line. Out of scope: Settings' search/save row logic shipped in Task 7141; any API change. Done means: - At 600px and 700px with the sidebar expanded, every knob's field, unit and default is readable without clipping (screenshots). - `./dc check full` green.

Settings knob rows now follow the card's width (container query, 452px) instead of the window's. At 600 and 700px with the sidebar expanded they stack with nothing clipped, and 1024px keeps three columns (visual check done). PR #5836 merged by the lane after full gate green. Sidebar auto-collapse deferred to draft #7183.