Two issues:
1. Icon badges read as a coloured glyph on a same-hue LIGHT tile
(bgcolor X.light + color X.main) — low contrast, "badly visible".
The AttendanceHistory month tile and the Dashboard 2FA-banner icon now
use a SOLID tile (X.main) + white glyph, matching the StatCard badge
convention. Readable in both schemes (verified: info.main #1d4ed8 light
/ #3b82f6 dark, error.main, white glyph).
2. Theme reverted to light on F5 while the toggle still showed dark.
Cause: two independent stores — our ThemeContext key (boha-theme) and
MUI's own cssVariables mode key (mui-mode). The toggle only wrote
boha-theme, so on mount MUI restored its stale mui-mode and overrode
data-theme. Collapsed to a SINGLE source of truth: ThemeContext now
reads/writes MUI's `mui-mode` key directly (with a one-time migration
from the legacy boha-theme, which is then removed). Verified: toggle
dark -> F5 -> stays dark; only `mui-mode` remains in localStorage.
tsc -b --noEmit, npm run build, vitest 152/152 clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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