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, 5 insertions, 5 deletions

diff --git a/test/snapshots/chordcut.golden b/test/snapshots/chordcut.golden
index d5266717..bff929b3 100644
--- a/test/snapshots/chordcut.golden
+++ b/test/snapshots/chordcut.golden
@@ -20,7 +20,7 @@
 |  ls
 |  f.txt  g.txt
 == snap cut grid=120x31 cursor=7,8
-|6:    /tmp/pardes-snap/chordcut/cwd/f.txt * Save Tty Collapse D
+|6:  * /tmp/pardes-snap/chordcut/cwd/f.txt * Save Tty Collapse D
 |8:      2  2
 == snap copied grid=120x31 cursor=10,9
 == snap pointpaste grid=120x31 cursor=16,10
@@ -30,7 +30,7 @@
 == snap cancelexec grid=120x31 cursor=25,8
 |8:      2  2echo B''OO g.txt
 == snap execafter grid=120x31 cursor=25,8
-|6:    /tmp/pardes-snap/chordcut/cwd/f.txt * Save Tty Collapse D   /tmp/pardes-snap/chordcut/cwd (echo B''OO) exit 0 Kill Sa
+|6:  * /tmp/pardes-snap/chordcut/cwd/f.txt * Save Tty Collapse D   /tmp/pardes-snap/chordcut/cwd (echo B''OO) exit 0 Kill Sa
 |7:      1 line 1                                          Exec   % echo B''OO
 |8:      2  2echo B''OO g.txt                                     BOO
 |9:      3 line 3                                                 exit 0
@@ -48,13 +48,13 @@
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-59 #e5eee5,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-59 #e5eee5,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |5: 0-0 d,#608269, 1-59 d,#0d1410, 60-60 d,#608269, 61-119 d,#0d1410,
-|6: 0-1 #ffffff,#496656, 2-2 d,#1d2824, 3-32 #b2c3b8,#1d2824, 33-37 #d3b0d9,#1d2824, 38-59 #b2c3b8,#1d2824, 60-61 #ffffff,#496656, 62-62 d,#1d2824, 63-119 #b2c3b8,#1d2824,
+|6: 0-0 #ffffff,#496656, 1-1 #000000,#f9cb70,b 2-2 d,#1d2824, 3-32 #b2c3b8,#1d2824, 33-37 #d3b0d9,#1d2824, 38-59 #b2c3b8,#1d2824, 60-61 #ffffff,#496656, 62-62 d,#1d2824, 63-119 #b2c3b8,#1d2824,
 |7: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |8: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-24 #e5eee5,#0d1410, 25-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |9: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |10: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-16 #e5eee5,#0d1410, 17-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |11: 0-0 d,#152019, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-13 #e5eee5,#0d1410, 14-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
-|12: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-32 #becfc4,#26362d, 33-37 #dfbce5,#26362d, 38-59 #becfc4,#26362d, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
+|12: 0-0 #000000,#add38a, 1-1 #000000,#f9cb70,b 2-2 d,#26362d, 3-32 #becfc4,#26362d, 33-37 #dfbce5,#26362d, 38-59 #becfc4,#26362d, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |13: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-10 #f5f7ee,#3c614a, 11-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |14: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |15: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
@@ -77,7 +77,7 @@
 |13: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 |14: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-12 #e5eee5,#0d1410, 13-59 d,#0d1410, 60-60 d,#608269, 61-61 d,#0d1410, 62-119 #e5eee5,#0d1410,
 == snap ttyprobe grid=120x31 cursor=42,22
-|12:    /tmp/pardes-snap/chordcut/cwd/g.txt * Save Tty Collapse D
+|12:  * /tmp/pardes-snap/chordcut/cwd/g.txt * Save Tty Collapse D
 |17: $  /tmp/pardes-snap/chordcut/cwd Tty+bash Save Mode Filter C
 |18:   $ ls
 |20:   $ stty -icanon -echo; printf '\x1b[?2004h\x1b[?1000h\x1b[?