fix(swaync): palette-safe pairings — text was invisible on summer-day (item 25)

Palette roles aren't uniform: summer-day and flexoki-light use subtext
as text-ON-surface (== base) and surface as a dark chip (== text), so
swaync's @subtext-on-@base body text and @surface/@text buttons were
self-colored (caught on the Latitude).

- body/summary: @text on @base — the one text pairing that passes in
  every palette (survey: worst WCAG ratio 5.18 across all 21 themes;
  subtext/base bottomed at 1.00 twice, muted/base at 1.27).
- hover rows + widget-title buttons: alpha(@text, 0.1) tints —
  contrast by construction; subtext/surface defines dropped.
- NEW checks.theme-contrast (tools/check-theme-contrast.py): asserts
  the hex-on-hex text pairings across themes/*.json, cheap (no VM).

The audit also found the generated waybar/rofi CSS shares the bug
class, live on flexoki-light (no whole-swap) → BACKLOG item 27.

Verified: V0; V1 (checks.theme-contrast builds green, 21 themes;
rendered services.swaync.style has zero @subtext/@surface). Honesty:
NOT visually verified — V3 queued (notify-send on summer-day).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/JOURNAL.md

@@ -17,6 +17,22 @@ Template:
 
 ---
 
+## 2026-07-04 — swaync contrast fix + theme-contrast check (iteration #9, item 25)
+- **Task:** BACKLOG NOW#25 — swaync text invisible on summer-day.
+- **Did:** swaync.nix now uses only palette-safe pairings: body/summary
+  = @text on @base (worst ratio 5.18 across all 21 themes; subtext/base
+  was 1.00 on summer-day + flexoki-light), hover rows + widget buttons
+  = alpha(@text, 0.1) tints (contrast by construction); dropped the
+  subtext/surface defines. NEW permanent check `checks.theme-contrast`
+  (tools/check-theme-contrast.py) asserts the hex-on-hex text pairings
+  across every theme JSON. Audit found the same mispairing in generated
+  waybar/rofi CSS, live on flexoki-light (no whole-swap) → NOW item 27.
+- **Verified:** V0; V1 — checks.theme-contrast builds green (21 themes),
+  rendered services.swaync.style contains zero @subtext/@surface.
+  NOT V2/V3-verified visually — queued (Bernardo is at the Latitude).
+- **Pending:** V3 notify-send readability check on summer-day; item 27.
+- **Next suggestion:** item 27 (same bug class, waybar/rofi surfaces).
+
 ## 2026-07-04 — SUPER+? bind fix (iteration #8, item 26)
 - **Task:** BACKLOG NOW#26 — cheatsheet bind never fires on hardware.
 - **Did:** keybinds.nix: `$mod, question` → `$mod SHIFT, question`