feat(gui): rebuild Overview from the egui GUI's own widgets

4.0.3 put the original CyberColors palette on a layout I had invented,
and it still did not look like simon. The layout was the larger half of
the problem, so this reads the original widgets out of git and ports
them rather than approximating them again.

The Glances-style QuickLook strip returns: four labelled mini-bars across
a 32px surface panel, threshold-coloured, each with its reading beside
it. Section headers are a 14px cyan title followed by a hairline rule to
the right edge -- the rule is what made a simon pane identifiable at a
glance and 4.0.0 dropped it entirely. Metric cards are back at their
original 140x70 with a 3px device-coloured stripe down the left edge, an
11px secondary title and an 18px value; the 4.0.3 tiles were three times
that size with a 30px number and no stripe. Below them a dense two-column
process table, split evenly, the way htop fills a terminal.

QuickLook draws no bar for counts. TASKS and DISKS are not percentages,
and a bar sitting at 0% reads as "nothing", which is the opposite of what
"32 tasks" means.

Removes stat_tile and panel, the widgets from the abandoned card-grid
approach, which clippy caught as dead once Overview stopped calling them.

840 tests, 0 failures. clippy -D warnings clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>