The two built-in launcher themes previously shared the same row radius,
padding, icon treatment, and selection fill (only mode/width/top/radius/
icon_px were themed), so breadbox's overlay rendered as one launcher
recoloured rather than two different instruments.
Adds row_radius, row_inset, row_padding_v/h, icon_radius, search_font_size,
search_padding_v/h, and selection_alpha to [launcher], all consumed by
breadbox's build_css in the paired breadbox commit. Sets liquid-motion to
the soft/roomy demo numbers (row radius 12, 28px icons, 22% selection alpha,
Recent/Apps section headers) and glass-workbench to the dense/technical demo
numbers (row radius 6, 22px icons, 28% selection alpha, flat list).
Also wires up three previously-declared-but-unconsumed tokens
(font_family, font_fallback, font_size_base) for breadbox's launcher panel
specifically — scoped consumption, not the full ecosystem-wide font system
replacement (breadbar/stylesheet() are unaffected). Updated the stale
doc comments in types.rs/mod.rs and both theme.toml files to match, and
updated the two existing launcher-geometry tests plus added a glass-workbench
equivalent.
Defaults for all new keys reproduce breadbox's pre-redesign hardcoded CSS
values, so themes that don't set them (spotlight's capsule doesn't read any
of this) are unaffected.