docs(user): themes — drop the invented 'default light theme' tag, per owner

Lupine's '(default light theme)' tag had no basis anywhere: the string
exists only in the ThemeType union, and there is no light-default logic
in theme.ts or the Appearance panel. Platform-owner clarification:
Tokyo Night is the sole default (fresh install); the Dark/Light control
is a list filter with per-half counts, not a theme toggle. The page now
says exactly that, keeps the code-verified bits (mode filter opens on
your current theme's half via ThemeModeOf, checkmark indicator, counts)
and states the one-default rule plainly.

docs/user/themes.md

@@ -34,7 +34,7 @@ full set of [Omarchy](https://omarchy.org) defaults alongside the classics:
 
 **Light**
 
-- **Lupine** - Clean light with violet-blue accents (default light theme)
+- **Lupine** - Clean light with violet-blue accents
 - **Tokyo Night Day** - Daylight counterpart of the default
 - **Solarized Light** - Precision contrast on warm paper
 - **One Light** - Atom's light theme
@@ -52,11 +52,17 @@ full set of [Omarchy](https://omarchy.org) defaults alongside the classics:
 
 1. In the sidebar, open the **Appearance** panel (palette icon, near the bottom)
 2. Use the **Dark / Light** switch at the top to show the half you want —
-   it opens on the half your current theme lives in
+   it opens on the half your current theme lives in, and each side shows
+   how many themes it holds. The switch only filters the list; it never
+   changes your theme by itself
 3. Pick a theme from the list — each option shows its color swatch, and your
    active theme is marked with a checkmark
 4. Your choice is saved automatically and synced across devices
 
+There is exactly one default: **Tokyo Night** on a fresh install. Nothing
+else is pre-selected for you — pick whichever theme you like from either
+half.
+
 On small screens, open the sidebar with the menu button in the top bar first.
 
 ## Wood Paneling