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, 6 insertions, 6 deletions

diff --git a/test/snapshots/mini.golden b/test/snapshots/mini.golden
index b75bbd2b..52737277 100644
--- a/test/snapshots/mini.golden
+++ b/test/snapshots/mini.golden
@@ -11,11 +11,11 @@
 |     4
 == style opened grid=90x23
 |0: 0-70 #b2c3b8,#1d2824, 71-89 d,#1d2824,
-|1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-89 d,#26362d,
+|1: 0-1 #ffffff,#887455, 2-2 d,#314738, 3-34 #becfc4,#314738, 35-89 d,#314738,
 |2: 0-1 #ffffff,#496656, 2-2 d,#1d2824, 3-28 #b2c3b8,#1d2824, 29-40 #d3b0d9,#1d2824, 41-62 #b2c3b8,#1d2824, 63-89 d,#1d2824,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-22 #e5eee5,#0d1410, 23-83 d,#0d1410, 84-84 d,#1d2824, 85-88 #b2c3b8,#1d2824, 89-89 d,#1d2824,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-89 d,#0d1410,
-|5: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-28 #becfc4,#26362d, 29-41 #dfbce5,#26362d, 42-63 #becfc4,#26362d, 64-89 d,#26362d,
+|5: 0-1 #000000,#add38a, 2-2 d,#314738, 3-28 #becfc4,#314738, 29-41 #dfbce5,#314738, 42-63 #becfc4,#314738, 64-89 d,#314738,
 |6: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-8 #e5eee5,#0d1410, 9-9 #c9a7ed,#0d1410, 10-12 #e5eee5,#0d1410, 13-15 #c9a7ed,#0d1410, 16-21 #b8d88a,#0d1410, 22-22 #e5eee5,#0d1410, 23-89 d,#0d1410,
 |7: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-8 #b9f480,#0d1410, 9-11 #c9a7ed,#0d1410, 12-25 #b9f480,#0d1410, 26-89 d,#0d1410,
 |8: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-17 #e5eee5,#0d1410, 18-19 #f8c082,#0d1410, 20-20 #e5eee5,#0d1410, 21-89 d,#0d1410,
@@ -37,7 +37,7 @@
 |0: Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 @0: 0-70 #b2c3b8,#1d2824,,tagline 71-89 d,#1d2824,,tagline
 |1:    New Tty Find Grep Joincol Delcol
-@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#26362d,,tagline 3-34 #becfc4,#26362d,,tagline 35-89 d,#26362d,,tagline
+@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#314738,,tagline 3-34 #becfc4,#314738,,tagline 35-89 d,#314738,,tagline
 |2:    /tmp/pardes-snap/mini/cwd/commands.txt Save Tty Collapse Del
 @2: 0-1 #ffffff,#496656,,tagline 2-2 d,#1d2824,,tagline 3-28 #b2c3b8,#1d2824,,tagline 29-40 #d3b0d9,#1d2824,,tagline 41-62 #b2c3b8,#1d2824,,tagline 63-89 d,#1d2824,,tagline
 |3:      1 @`Mini demo.zig`                                                              Mini
@@ -45,7 +45,7 @@
 |4:
 @4: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-89 d,#0d1410,,body
 |5:    /tmp/pardes-snap/mini/cwd/Mini demo.zig Save Tty Collapse Del
-@5: 0-1 #000000,#add38a,,tagline 2-2 d,#26362d,,tagline 3-28 #becfc4,#26362d,,tagline 29-41 #dfbce5,#26362d,,tagline 42-63 #becfc4,#26362d,,tagline 64-89 d,#26362d,,tagline
+@5: 0-1 #000000,#add38a,,tagline 2-2 d,#314738,,tagline 3-28 #becfc4,#314738,,tagline 29-41 #dfbce5,#314738,,tagline 42-63 #becfc4,#314738,,tagline 64-89 d,#314738,,tagline
 |6:      1 ⠭⠍⣥⢩⣭⡭⣭⣬⣌⢭⣭⠌⠬⠅⠍⠁
 +6: 7="⠭" 8="⠍" 9="⣥" 10="⢩" 11="⣭" 12="⡭" 13="⣭" 14="⣬" 15="⣌" 16="⢭" 17="⣭" 18="⠌" 19="⠬" 20="⠅" 21="⠍" 22="⠁"
 @6: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #616f64,#0d1410,b,body 7-8 #e5eee5,#0d1410,,body 9-9 #c9a7ed,#0d1410,,body 10-12 #e5eee5,#0d1410,,body 13-15 #c9a7ed,#0d1410,,body 16-21 #b8d88a,#0d1410,,body 22-22 #e5eee5,#0d1410,,body 23-89 d,#0d1410,,body
@@ -120,7 +120,7 @@
 |0: Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 @0: 0-70 #b2c3b8,#1d2824,,tagline 71-104 d,#1d2824,,tagline
 |1:    New Tty Find Grep Joincol Delcol
-@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#26362d,,tagline 3-34 #becfc4,#26362d,,tagline 35-104 d,#26362d,,tagline
+@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#314738,,tagline 3-34 #becfc4,#314738,,tagline 35-104 d,#314738,,tagline
 |2:    /tmp/pardes-snap/mini/cwd/commands.txt Save Tty Collapse Del
 @2: 0-1 #ffffff,#496656,,tagline 2-2 d,#1d2824,,tagline 3-28 #b2c3b8,#1d2824,,tagline 29-40 #d3b0d9,#1d2824,,tagline 41-62 #b2c3b8,#1d2824,,tagline 63-104 d,#1d2824,,tagline
 |3:      1 @`Mini demo.zig`
@@ -130,7 +130,7 @@
 |5:
 @5: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-104 d,#0d1410,,body
 |6:    /tmp/pardes-snap/mini/cwd/Mini demo.zig Save Tty Collapse Del
-@6: 0-1 #000000,#add38a,,tagline 2-2 d,#26362d,,tagline 3-28 #becfc4,#26362d,,tagline 29-41 #dfbce5,#26362d,,tagline 42-63 #becfc4,#26362d,,tagline 64-104 d,#26362d,,tagline
+@6: 0-1 #000000,#add38a,,tagline 2-2 d,#314738,,tagline 3-28 #becfc4,#314738,,tagline 29-41 #dfbce5,#314738,,tagline 42-63 #becfc4,#314738,,tagline 64-104 d,#314738,,tagline
 |7:      1 ⠭⠍⣥⢩⣭⡭⣭⣬⣌⢭⣭⠌⠬⠅⠍⠁                                                                           Colors
 +7: 7="⠭" 8="⠍" 9="⣥" 10="⢩" 11="⣭" 12="⡭" 13="⣭" 14="⣬" 15="⣌" 16="⢭" 17="⣭" 18="⠌" 19="⠬" 20="⠅" 21="⠍" 22="⠁"
 @7: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #616f64,#0d1410,b,body 7-8 #e5eee5,#0d1410,,body 9-9 #c9a7ed,#0d1410,,body 10-12 #e5eee5,#0d1410,,body 13-15 #c9a7ed,#0d1410,,body 16-21 #b8d88a,#0d1410,,body 22-22 #e5eee5,#0d1410,,body 23-96 d,#0d1410,,body 97-97 d,#1d2824,,tagline 98-103 #b2c3b8,#1d2824,,tagline 104-104 d,#1d2824,,tagline