acme looks like acme; every theme gets acme's button, scroll column and 2px rules

acme takes plan9port's own colours (acme.c iconinit, draw.h): selections
#eeee9e in the body and #9eeeee in the tag, black ink; exec and look sweeps
#aa0000 and #006600, white ink; a #99994c scrollbar under a #ffffea thumb;
black rules; a #8888cc tag/body rule and column button.

Every theme: the grip is acme's button, its tag row's full height, in one
scroll column with the scrollbar (rail_px, 12 at a 17px tagline, scaled,
times GripWidth, a percent, default 150; same x0/x1 to the pixel):
focused clean = solid box; focused dirty = box_dirty filled to a box ring
(acme's modbutton); unfocused clean = a box_border ring round the tag's
ground; unfocused dirty = box_dirty a pixel inside that ring. The grid, which
has no ring, marks dirty with a bold * on box_dirty in the grip's second cell
and fills an unfocused grip halfway to its ring. Regions carry a dirty flag.
Column buttons are the same shape, solid. 2px rules between columns and
stacked panes (inside the tag band's slack), none at the window edge; a 1px
tag/body rule halfway between tag and page.

Theme data: tag_sel_bg, sweep_bg/fg, tag_rule, rule_px, rail_px, box_border,
box_dirty. Chrome: rule_px, tag_rule, rail_px, grip_border, grip_focus_ring;
a comptime guard on Chrome's layout forces a wire bump once v8 ships.
Structural rules are exempt from the focus-indicator rule (docs/effects.md).

Tests: acme widths; stacked rule in the slack at two tagline sizes; every
grip-column pixel is band, button, ring or rule, and the button shares the
scrollbar's x0/x1 (4 metrics x top/bottom x focus x dirty); the four grip
states distinct in every native theme with a non-colour dirty cue in the
grid; wire round-trip of the new fields.

Shared files: src/colors.zig, src/surface.zig, src/body_layer.zig,
src/tagline.zig, src/detached/wire.zig, docs/themes.md, docs/config.md,
docs/effects.md, 21 snapshot goldens (the grip cells only),
test/gui-goldens.txt.

Motion flavours differ by design, and drive notice drops and pane moves

1 files changed, 6 insertions, 6 deletions

diff --git a/test/snapshots/lsprelpath.golden b/test/snapshots/lsprelpath.golden
index 96dc4c99..e2201d5c 100644
--- a/test/snapshots/lsprelpath.golden
+++ b/test/snapshots/lsprelpath.golden
@@ -1,7 +1,7 @@
 == snap absrow grid=100x35 cursor=16,7
 |Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 |   New Tty Find Grep Joincol Delcol
-|^  /tmp/pardes-snap/lsprelpath/cwd/sub/parent.zig * Save Tty Collapse Del TreeContext
+|^* /tmp/pardes-snap/lsprelpath/cwd/sub/parent.zig * Save Tty Collapse Del TreeContext
 |     1 const shade = @import("../shade.zig");
 |     2
 |     3 pub fn pick(s: shade.Shade) u8 {
@@ -35,7 +35,7 @@
 |     1 /tmp/pardes-snap/lsprelpath/cwd/shade.zig:2:5-13 verdigris  verdigris,
 |     2 /tmp/pardes-snap/lsprelpath/cwd/shade.zig:3:5-12 cinnabar  cinnabar,
 == snap abslook grid=100x35 cursor=19,19
-|2:    /tmp/pardes-snap/lsprelpath/cwd/sub/parent.zig * Save Tty Collapse Del TreeContext
+|2:  * /tmp/pardes-snap/lsprelpath/cwd/sub/parent.zig * Save Tty Collapse Del TreeContext
 |17:    /tmp/pardes-snap/lsprelpath/cwd/shade.zig Save Tty Collapse Del TreeContext
 |18:      1 pub const Shade = enum {
 |19:      2     verdigris,
@@ -45,7 +45,7 @@
 == style abslook grid=100x35
 |0: 0-70 #b2c3b8,#1d2824, 71-99 d,#1d2824,
 |1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-99 d,#26362d,
-|2: 0-1 #ffffff,#496656, 2-2 d,#1d2824, 3-38 #b2c3b8,#1d2824, 39-48 #d3b0d9,#1d2824, 49-84 #b2c3b8,#1d2824, 85-99 d,#1d2824,
+|2: 0-0 #ffffff,#496656, 1-1 #000000,#f9cb70,b 2-2 d,#1d2824, 3-38 #b2c3b8,#1d2824, 39-48 #d3b0d9,#1d2824, 49-84 #b2c3b8,#1d2824, 85-99 d,#1d2824,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-20 #e5eee5,#0d1410, 21-27 #c9a7ed,#0d1410, 28-28 #e5eee5,#0d1410, 29-42 #b8d88a,#0d1410, 43-44 #e5eee5,#0d1410, 45-99 d,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-99 d,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-10 #e5eee5,#0d1410, 11-12 #c9a7ed,#0d1410, 13-38 #e5eee5,#0d1410, 39-99 d,#0d1410,
@@ -81,7 +81,7 @@
 == snap subrow grid=100x35 cursor=16,7
 |Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 |   New Tty Find Grep Joincol Delcol
-|^  /tmp/pardes-snap/lsprelpath/cwd/sub/subdir.zig * Save Tty Collapse Del TreeContext
+|^* /tmp/pardes-snap/lsprelpath/cwd/sub/subdir.zig * Save Tty Collapse Del TreeContext
 |     1 const tint = @import("inner/tint.zig");
 |     2
 |     3 pub fn hue(t: tint.Tint) u8 {
@@ -115,7 +115,7 @@
 |     1 inner/tint.zig:2:5-9 ochre  ochre,
 |     2 inner/tint.zig:3:5-10 indigo  indigo,
 == snap sublook grid=100x35 cursor=15,19
-|2:    /tmp/pardes-snap/lsprelpath/cwd/sub/subdir.zig * Save Tty Collapse Del TreeContext
+|2:  * /tmp/pardes-snap/lsprelpath/cwd/sub/subdir.zig * Save Tty Collapse Del TreeContext
 |17:    /tmp/pardes-snap/lsprelpath/cwd/sub/inner/tint.zig Save Tty Collapse Del TreeContext
 |18:      1 pub const Tint = enum {
 |19:      2     ochre,
@@ -125,7 +125,7 @@
 == style sublook grid=100x35
 |0: 0-70 #b2c3b8,#1d2824, 71-99 d,#1d2824,
 |1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-99 d,#26362d,
-|2: 0-1 #ffffff,#496656, 2-2 d,#1d2824, 3-38 #b2c3b8,#1d2824, 39-48 #d3b0d9,#1d2824, 49-84 #b2c3b8,#1d2824, 85-99 d,#1d2824,
+|2: 0-0 #ffffff,#496656, 1-1 #000000,#f9cb70,b 2-2 d,#1d2824, 3-38 #b2c3b8,#1d2824, 39-48 #d3b0d9,#1d2824, 49-84 #b2c3b8,#1d2824, 85-99 d,#1d2824,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-19 #e5eee5,#0d1410, 20-26 #c9a7ed,#0d1410, 27-27 #e5eee5,#0d1410, 28-43 #b8d88a,#0d1410, 44-45 #e5eee5,#0d1410, 46-99 d,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-99 d,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-10 #e5eee5,#0d1410, 11-12 #c9a7ed,#0d1410, 13-35 #e5eee5,#0d1410, 36-99 d,#0d1410,