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, 14 insertions, 14 deletions

diff --git a/test/gui-goldens.txt b/test/gui-goldens.txt
index 586c8985..263f1bcc 100644
--- a/test/gui-goldens.txt
+++ b/test/gui-goldens.txt
@@ -1,17 +1,17 @@
-01-boot 39c940960ccd264a0ed2e9dd99a2c352a47ca64c67d42e3313ae344713c712ae
-02-second-document 9a810fe372fa37bc3d338d7f0bd04b5224957cb57ef63952c8fc02d1e72e705a
-03-notice b52ebd3860694d35a43e56d149d180249b2609d4a3fc4374347d8cd3b5ebc05c
-04-context-rows-mid-thumb e7b9f5d6da06143fff79b9f2686c29050556173f97c759a4119a201542f993ef
-05-body-selection 06b7cbcf368bb4371873b26f70286fb2b5ada4293b758fa73458157a248c7aa6
-06-tag-focus-selection a781c95cebb8c47a5c5168e1b7f9747f44a0aad043cc4eec1338bb1f08d0a340
-07-prompt-notice 03bdefcd99ccbf4849d2c2f6b561cee6c24263a1be70d55ecb9550a815506e0e
-08-wide-glyph-edges 9c7449be42c46ebbdbdcf156fbfbbe23d6e451720afde966659b1bd96b6886bc
-09-collapsed-focus-tint 807bd7621d54948b84cf2965ef463d3928d050259e8ee2d27472b1d3d378f91e
-10-tagbottom 03086852528d9c8a76f5926a7e7ee371200da617db279f42cbbb6825b5f41fce
-12-multiline-tag cd12edf85d9f472fc79aac91669f5d37619e0cc0ceedd1fe22d100faa127b685
-13-image f9412d7bbe0ebdb53bc62145c51ad3028d2f07cc3e9d2e52a3aeb89de7db6da3
-14-theme-ink da6369bd141a2d71aabb91854e82da88026926e0c931d89947645c090896b5d3
+01-boot 334054bba79ffb64553c2ed50dece720badf811eebc1f37fcbb859e90494dc56
+02-second-document 83a0b43c4bbfa47dbb35af854ce888a8f2ee2db21cf207c011ae6d4005068409
+03-notice 2c276935562be85dc807ecca7f35ef2affec1022f08efb134b7313c4866edaf1
+04-context-rows-mid-thumb f4178af9945946e2ae943dddbdf84b756dab45f2f42347bd25ca165ddf5b08e8
+05-body-selection 96a158adac982f4141526d10956e19828632edc0f6f60d1161d1353e34797118
+06-tag-focus-selection 94aff8499a6e6f399761ffdd56369d526fbe65232eb21c88addd12973af611aa
+07-prompt-notice 041603b841605b0a9456cbbb9b3e06e219b0a08a58e2d38229e1c81366577a87
+08-wide-glyph-edges 94b0beb7cc2f2a09259f4f7d57999001ef75ed53ea210a65a1510404bd161af9
+09-collapsed-focus-tint 83db5e1acb69424c8ecdb247fcf359ff6b010a529a628012991d74b4a6428b89
+10-tagbottom 3a7d5bc8b2e821ffb082ccd548c6f312947f614be80324fbd79b4182e34cf387
+12-multiline-tag 93cdcfa151dc823d3d13af270157dcca8f69ecfd0ace7e0b888c088ca8c3deaf
+13-image f609043fc0fcdb55369b836b61fcbc631f786cc2295a5ddd72c0d9a59b177a60
+14-theme-ink 881b7e99f38ad4aa3c46d2c61e20598010175d7858712a67fa6638fc29f12e14
 15-theme-acme-light ca5252f5117ac8d6c679cef917c9f316c9ca311fc7a8dcbac2796b4fc04d3b64
 16-debug 591bb7c45b4b9c46cd2458330b4fa3962afc6dac827fa6f5e20e927a72c586e6
 17-terminal 38299427891e31de0b5597159501c161474620eb26fd7708a6396f0fd685209e
-18-mid-transition c914231ea8c32446a0975cfbe338cb3b248a86f3d58c6bc56af6c3e800906302
+18-mid-transition ab31f5fde35367edda6c7f4e45bf4396596f242a60938f384df6c392bd3712d2