fixed missing period times in the ios widget ruler and unreadable tiles on tinted and clear home screens

A .systemLarge widget only gets ~27pt per period, below the 30pt threshold
shared with Android, so iOS now shows the times from 24pt with a tighter
cell. In non-full-color rendering modes the opaque tiles and the today
circle flattened into solid slabs hiding their text; they are drawn
translucent with an outline there and use the light-text palette.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ios/TimetableWidgetExtension/TimetableWidgetExtension.swift

@@ -201,12 +201,15 @@ private struct WidgetSurface<Content: View>: View {
     let entry: TimetableEntry
     @ViewBuilder let content: () -> Content
     @Environment(\.colorScheme) private var colorScheme
+    @Environment(\.widgetRenderingMode) private var renderingMode
 
     var body: some View {
-        let palette = WidgetPalette.resolve(
-            themeMode: entry.themeMode,
-            colorScheme: colorScheme
-        )
+        // Tinted / clear home screens map every colour to its luminance, so
+        // the light palette's near-black text would vanish — use the dark
+        // palette's light text there regardless of the theme setting.
+        let palette = renderingMode == .fullColor
+            ? WidgetPalette.resolve(themeMode: entry.themeMode, colorScheme: colorScheme)
+            : .dark
         return AnyView(
             background(content: content(), palette: palette)
                 .environment(\.widgetPalette, palette)