docs(design): log the touch header search

docs/DESIGN.md

@@ -712,3 +712,4 @@ of a full-width panel and nothing on the right.
 | 2026-10-04 | E35 Lint for z-levels and edged labels | Both rules stay; the two eslint selectors (`Z_RAW`, `EDGED_LABEL`) that refused them go | Keep the selectors | 0 hits since the E28 sweep that fixed the sites: a check that never fires costs a probe test and a snapshot each, and the UI review holds both rules |
 | 2026-10-06 | `player` focus | A dialog that is a player opens focused on its panel (the YouTube player's rule, now `Modal`'s too); on the media element itself, Space and the arrows stay the element's own | `close`, or the media element | On the ✕ Space closed the player; on the element the browser's own controls acted on the same key as the player's (one Space played and paused, measured in Chrome) |
 | 2026-10-08 | Captions on touch | A `Tooltip` opens for a mouse and a key's focus only, never for a finger | A caption on tap; a long-press caption | On an iPad the tap that showed the caption was taken as a hover and lost its click (every rail button took two taps), and no finger sends the mouseleave that hides it; the rail's labels setting names the buttons on touch |
+| 2026-10-08 | Header search on touch | No key cap on a touch screen; the pill grows to 52 px so a ring shows round the 44 px Go; Go drops to its icon by the column's width | Keep the key cap; a 44 px Go overhanging a 40 px pill | On a tablet the 44 px key cap and Go sat on the pill's edge and cut the placeholder; an overhanging Go breaks the nested radii |