Extends the dark-logo fix to the customer login, customer accept-invite,
customer reset-password, and gallery client-access pages — they all rendered
only the light logo on the themed (possibly dark) surface.
Also makes the login-page pick frame-aware: a framed login logo sits on a
fixed cream plate, so the light (dark-ink) logo always reads there; only the
frameless logo sits on the themed page background and uses the dark variant.
This corrects the admin login too (was unconditionally swapping when dark).
Customer/gallery pages read isDark from usePublicDarkMode (branding_force_
color_mode + OS fallback), matching CustomerLayout.