Rules and chrome scale with the display's density; dark pages get visible separators and focus tints

Density: dp() in gui.zig draws every size given in pixels in logical
pixels (SDL's window display scale, rounded, at least one), as acme scales
Border, ButtonBorder and Scrollgap: the rules (rule_px), the tag rule, the
grip's ring, its dirty gap and mode bars, the rail's gap to the text and
its minimum, the thumb's inset, the rim, a bar cursor's minimum width,
underline and strikethrough thickness (the atlas is dropped on a scale
change), the rule-grab margin, and the Crt's scanline and mask periods
(pardesScale in the post prefix). Cell- and tagline-measured sizes stay:
the rail's width, Lift's blur and offsets, every motion; iResolution,
fragCoord and iMouse stay in the display's pixels, as ghostty's.
PARDES_TEST_SCALE forces a density in a harness (a test window is 1x
otherwise, whatever display it lands on) and sizes the test font with it.

Colours: a separator that stands off its page by less than 1.5:1 is lifted
toward the text to 1.6:1 (helix, atelier, paper; a theme with no page,
dark, is judged against #121212), and empty_col follows it. forge's own
rule already stands at 3.83:1; what hid it was density: 2 device pixels
on a 3x screen, now 6 (dp). A focused tag's tint closer than 1.5:1 to the
plain tag on a dark page (1.25:1 on a light one) is pushed further the way
it leans, as far as its text keeps its own contrast or 4.5: forge
1.23 -> 1.51 (#2d3440 -> #374253), and likewise dusk, orchard, ink,
lagoon, clay, harvest, spectrum, solarium, forge_soft; daybreak, atelier,
paper to 1.25. dark and helix gain a tint of their own (dark: #484566
under #c8c8c8, 1.54:1; helix: ramp 237 under 250, 1.65:1).

Tag caret: past a full row's end, the G3 glide box sits on the tag's right
edge, where the layer's caret and the pixel shell's are.

Tests: every native theme's separator >= 1.5 and every dark one has a
tint >= 1.25 with readable text; forge keeps its own border; the tag caret
glide box at a full row; at 2x the spine, tag rule, ring, rail start and
gap, and bar cursor double. Legacy-ThemeFile test strips helix's new pair.

Goldens: snapshot goldens change in colour rows only, the tints (orchard
#283a2f -> #314738 at boot, forge, helix and dark in theme/themesel).
GUI goldens: the harness's single Del of the renamed wide pane is refused
since ysqnkyoy (a rename counted as unsaved; fixed on the 9P line in
wkzlsqvy), so scenes 09-17 were recorded with that pane open and the file
was stale since the merge (08 and 18 also moved with ykvnltvs's full-row
tag wrap). The goldens here were recorded with that pane closed (as
wkzlsqvy will close it); against the parent's binary under the same
conditions they differ only in the tints: 01-13 forge's (#2d3440 ->
#374253, and the glyph edges on it), 14 ink's; 15-18 are byte-identical.
Until wkzlsqvy is merged, a run here fails 09-17. Each commit reproduces its own
recorded goldens on this machine (checked at kvtmqkyn). A test window is
1x unless PARDES_TEST_SCALE says otherwise, whatever display it opens on.
Prebuilt shaders refreshed from their sources.
Captures: .scratch/render/dark-borders/{before,after,compare,scale2,scale3}.

1 files changed, 4 insertions, 4 deletions

diff --git a/test/snapshots/syntax.golden b/test/snapshots/syntax.golden
index 3e3679c6..70e548b4 100644
--- a/test/snapshots/syntax.golden
+++ b/test/snapshots/syntax.golden
@@ -21,12 +21,12 @@
 |  demo.zig
 == style zig-open grid=150x31
 |0: 0-70 #b2c3b8,#1d2824, 71-149 d,#1d2824,
-|1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-74 d,#26362d, 75-76 #ffffff,#887455, 77-77 d,#1d2824, 78-109 #b2c3b8,#1d2824, 110-149 d,#1d2824,
+|1: 0-1 #ffffff,#887455, 2-2 d,#314738, 3-34 #becfc4,#314738, 35-74 d,#314738, 75-76 #ffffff,#887455, 77-77 d,#1d2824, 78-109 #b2c3b8,#1d2824, 110-149 d,#1d2824,
 |2: 0-1 #ffffff,#496656, 2-2 d,#1d2824, 3-30 #b2c3b8,#1d2824, 31-38 #d3b0d9,#1d2824, 39-68 #b2c3b8,#1d2824, 69-74 d,#1d2824, 75-76 #ffffff,#496656, 77-77 d,#1d2824, 78-105 #b2c3b8,#1d2824, 106-113 #d3b0d9,#1d2824, 114-143 #b2c3b8,#1d2824, 144-149 d,#1d2824,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-74 #e5eee5,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-74 #e5eee5,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |5: 0-0 d,#608269, 1-74 d,#0d1410, 75-75 d,#608269, 76-149 d,#0d1410,
-|6: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-30 #becfc4,#26362d, 31-38 #dfbce5,#26362d, 39-72 #becfc4,#26362d, 73-74 d,#26362d, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
+|6: 0-1 #000000,#add38a, 2-2 d,#314738, 3-30 #becfc4,#314738, 31-38 #dfbce5,#314738, 39-72 #becfc4,#314738, 73-74 d,#314738, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |7: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-18 #e5eee5,#0d1410, 19-25 #c9a7ed,#0d1410, 26-26 #e5eee5,#0d1410, 27-31 #b8d88a,#0d1410, 32-34 #e5eee5,#0d1410, 35-42 #b9f480,#0d1410, 43-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |8: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-10 #e5eee5,#0d1410, 11-12 #c9a7ed,#0d1410, 13-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |9: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-23 #e5eee5,#0d1410, 24-25 #f8c082,#0d1410, 26-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
@@ -54,7 +54,7 @@
 == style colors-off grid=150x31
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-3 #e5eee5,#0d1410, 4-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-78 #e5eee5,#0d1410, 79-149 d,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-9 #e5eee5,#0d1410, 10-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-84 #e5eee5,#0d1410, 85-149 d,#0d1410,
-|6: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-30 #becfc4,#26362d, 31-38 #dfbce5,#26362d, 39-72 #becfc4,#26362d, 73-74 d,#26362d, 75-75 d,#608269, 76-149 d,#0d1410,
+|6: 0-1 #000000,#add38a, 2-2 d,#314738, 3-30 #becfc4,#314738, 31-38 #dfbce5,#314738, 39-72 #becfc4,#314738, 73-74 d,#314738, 75-75 d,#608269, 76-149 d,#0d1410,
 |7: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-42 #e5eee5,#0d1410, 43-66 d,#0d1410, 67-67 d,#1d2824, 68-73 #b2c3b8,#1d2824, 74-74 d,#1d2824, 75-75 d,#608269, 76-149 d,#0d1410,
 |8: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-149 d,#0d1410,
 |9: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-149 d,#0d1410,
@@ -82,7 +82,7 @@
 == style colors-on grid=150x31
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-74 #e5eee5,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-74 #e5eee5,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
-|6: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-30 #becfc4,#26362d, 31-38 #dfbce5,#26362d, 39-72 #becfc4,#26362d, 73-74 d,#26362d, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
+|6: 0-1 #000000,#add38a, 2-2 d,#314738, 3-30 #becfc4,#314738, 31-38 #dfbce5,#314738, 39-72 #becfc4,#314738, 73-74 d,#314738, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |7: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-18 #e5eee5,#0d1410, 19-25 #c9a7ed,#0d1410, 26-26 #e5eee5,#0d1410, 27-31 #b8d88a,#0d1410, 32-34 #e5eee5,#0d1410, 35-42 #b9f480,#0d1410, 43-66 d,#0d1410, 67-67 d,#1d2824, 68-73 #b2c3b8,#1d2824, 74-74 d,#1d2824, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |8: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-10 #e5eee5,#0d1410, 11-12 #c9a7ed,#0d1410, 13-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,
 |9: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-23 #e5eee5,#0d1410, 24-25 #f8c082,#0d1410, 26-26 #e5eee5,#0d1410, 27-74 d,#0d1410, 75-75 d,#608269, 76-76 d,#0d1410, 77-149 #e5eee5,#0d1410,