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/TimetableWeekView.swift

@@ -4,6 +4,7 @@ import WidgetKit
 struct TimetableWeekView: View {
     let entry: TimetableEntry
     @Environment(\.widgetPalette) private var palette
+    @Environment(\.widgetRenderingMode) private var renderingMode
 
     var body: some View {
         ZStack {
@@ -115,13 +116,23 @@ struct TimetableWeekView: View {
                 .lineLimit(1)
             Text("\(Calendar.current.component(.day, from: day))")
                 .font(.system(size: 11, weight: isToday ? .bold : .regular))
-                .foregroundStyle(isToday ? palette.onAccent : palette.textPrimary)
+                .foregroundStyle(isToday ? todayNumberColor : palette.textPrimary)
                 .lineLimit(1)
                 .frame(width: 18, height: 18)
-                .background(Circle().fill(isToday ? palette.accent : Color.clear))
+                .background(Circle().fill(isToday ? todayCircleColor : Color.clear))
         }
     }
 
+    // An opaque accent circle flattens to the same shade as its number on
+    // tinted / clear home screens; keep the circle translucent there.
+    private var todayCircleColor: Color {
+        renderingMode == .fullColor ? palette.accent : Color.white.opacity(0.3)
+    }
+
+    private var todayNumberColor: Color {
+        renderingMode == .fullColor ? palette.onAccent : palette.textPrimary
+    }
+
     private func placeholder(_ message: String) -> some View {
         VStack(spacing: 4) {
             Text("Marianum Stundenplan")