Per review on #1715: the light-theme cap was a fixed absolute luminance (0.2) tuned for near-white backgrounds. On a mid-light shipped theme like light-poimandres (statusLineBg #7390aa, luminance ~0.55) that still left accents at only ~1.8-2.4:1. Theme now exposes statusLineLuminance + accentSurfaceLuminance; getSessionAccentHex takes the surface luminance and caps the accent to guarantee >=3:1 (WCAG AA large) against the actual surface, so near-white and mid-light light themes are both legible. Tests assert contrast across light + mid-light surfaces.
Per review on #1715: Theme.isLight drove accent darkening from userMessageBg, but the accents render on the status line / editor chrome. Themes that style the chat bubble darker than the status line (e.g. built-in porcelain: userMessageBg #5070a0, statusLineBg #f8f9fc) misclassified, leaving the bright dark-theme accent on a light status line. Derive isLight from statusLineBg; add a regression test over porcelain / light-catppuccin / dark-catppuccin.
can1357