Motion flavours, and Lift is shadow, rim or auto: auto on a dark page recedes the other panes (InactiveDim)

Motion off|crisp|smooth|bouncy|playful is one parameter set (animation.Motion)
every fx animation reads. One focus spring per pane drives both the lift and
the dim, at the flavour's pace; a grid snaps.

Lift drops glow and surface. A shadow falls on pane bodies and rails only,
capped so text and the selection keep min(contrast, 4.5); rim is a hairline
along the focused tag's top. auto is a shadow on a light page; on a dark page
the core recedes the unfocused panes' text (InactiveDim, ported from 2e4d97f,
default 30 under auto) with the same floor. Tests: focused text contrast is
never below unfocused in any style, dim or theme; the focused pane's cells and
tag are untouched by a dim.

Shared files: src/config.zig, src/builtins.zig, src/ninep/ctl.zig,
src/surface.zig, src/detached/wire.zig, docs/config.md,
test/snapshots/builtins.snap (one more wheel for the longer help).

1 files changed, 3 insertions, 0 deletions

diff --git a/src/surface.zig b/src/surface.zig
index e7149155..f16993a8 100644
--- a/src/surface.zig
+++ b/src/surface.zig
@@ -398,6 +398,9 @@ pub const Chrome = struct {
     scroll_thumb: [3]u8 = .{ 0, 0, 0 },
     /// The theme's accent (a glow's tint).
     accent: [3]u8 = .{ 0, 0, 0 },
+    /// A selection's text and ground: a lift keeps their contrast too.
+    sel_fg: [3]u8 = .{ 0, 0, 0 },
+    sel_bg: [3]u8 = .{ 0, 0, 0 },
     /// How a lifted part stands off the page (config.Runtime.LiftStyle).
     lift_style: u8 = 0,
 };