Hover/focus tooltips on icon-only and ambiguous…

Details

Adds a small data-tip primitive (::before pseudo-element, hover + keyboard
focus-visible) and applies it to controls whose meaning isn't fully carried
by their visible label or icon:
- The three floating glass toggles (gravity / weather / theme) — icon-only.
- The top-nav ⌘K "Jump to" chip — clarifies it opens a search palette.
- The v2 / v1 version chips — name the design each links to.
- The contact "Copy email" button — surfaces the address that'll be copied.
The version chip group lost its overflow:hidden (it was clipping tooltips);
the segmented pill is preserved by rounding the end chips individually.
The tooltip resets text-transform so chip-uppercase doesn't leak in.
Aria-labels are untouched — the tip is visual only. Reduced-motion drops
the fade transition.

Files changed (6)