Below 600px seven tabs plus a usable search field no longer fit. The bar
now reads logo | search | menu:
- The nav entries are repeated in the hamburger dropdown (shown there
only at <=600px) and the main nav is hidden.
- The search collapses to a round magnifier and expands into a fixed
overlay covering the header row on focus; Escape or a click elsewhere
returns it to the button.
- SettingsManager.setNavEntryVisible keeps both copies of the opt-in
entries (Other, Workflows) in sync when the switches are flipped.
- The dropdown scrolls when its 12 entries do not fit the viewport.
Verified in a headless browser from 320px to 1920px: no clipping and no
overlap, and the menu keeps its five actions above 600px.