Drops the separate dashboard tile and the top-level "+" button so the
sidebar's first row holds a single workspace identity. "+ New
workspace" lives inside the disclosure popover next to the existing
spaces list, matching that row's geometry instead of inventing a new
square tile.
The previous 76 px traffic-light reserve only cleared the buttons
when the row also carried the tile and "+" — with the pill alone
plus its drop-shadow, it slid back behind the green button on the
default sidebar width. Widen `TRAFFIC_LIGHT_RESERVE` to 100 px and
document the derivation: pill outer left = `29 + RESERVE`, traffic-
light group right edge ≈ 112 px, so 100 leaves 17 px of breathing
room. Anchor solver and tests track the new geometry.
ZacharyZhang-NY
a6620fa265