fix: sun position arc overflow and revert user display

- Constrain arc height to fit within card boundaries
- Scale radius down when arc would overflow on wider displays
- Revert user display in section header, use debugPrint instead

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/shared/widgets/sun_position_widget.dart

@@ -386,7 +386,15 @@ class _SunArcPainter extends CustomPainter {
 
     // Calculate radius so arc endpoints touch horizon
     // For a chord of width W and arc angle θ: R = W / (2 * sin(θ/2))
-    final radius = horizonWidth / (2 * math.sin(clampedAngle / 2));
+    var radius = horizonWidth / (2 * math.sin(clampedAngle / 2));
+
+    // Constrain arc height to fit within available space (leave 25px margin for sun)
+    final maxArcHeight = size.height - horizonY - 25;
+    final arcHeight = radius * (1 - math.cos(clampedAngle / 2));
+    if (arcHeight > maxArcHeight) {
+      // Scale radius down to fit
+      radius = maxArcHeight / (1 - math.cos(clampedAngle / 2));
+    }
 
     // Arc center is below the horizon for an upward-bulging arc
     // Distance from chord to center = R * cos(θ/2)
@@ -491,7 +499,15 @@ class _SunArcPainter extends CustomPainter {
     final clampedAngle = arcAngle.clamp(math.pi / 6, math.pi);
 
     // Calculate radius so arc endpoints touch horizon
-    final radius = horizonWidth / (2 * math.sin(clampedAngle / 2));
+    var radius = horizonWidth / (2 * math.sin(clampedAngle / 2));
+
+    // Constrain arc height to fit within available space (leave 20px margin for moon)
+    final maxArcHeight = size.height - horizonY - 20;
+    final arcHeight = radius * (1 - math.cos(clampedAngle / 2));
+    if (arcHeight > maxArcHeight) {
+      // Scale radius down to fit
+      radius = maxArcHeight / (1 - math.cos(clampedAngle / 2));
+    }
 
     // Arc center is below the horizon for an upward-bulging arc
     final horizonYPos = size.height - horizonY;