* fix(ui): allow DefaultTheme "Auto" from config When DefaultTheme is set to "Auto" in the server config, the defaultTheme() function in themeReducer now returns AUTO_THEME_ID instead of falling through to the DarkTheme fallback. This allows useCurrentTheme to correctly read prefers-color-scheme and select Light or Dark theme automatically for new/incognito users. Adds themeReducer unit tests covering Auto, named-theme, and unrecognized-value fallback paths. * chore: format Signed-off-by: Deluan <[email protected]> --------- Signed-off-by: Deluan <[email protected]> Co-authored-by: Deluan <[email protected]>