[CircularProgressIndicator] Full circle track has seam artifact due to cap overlap at 0°

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## Description

When `CircularDrawingDelegate.drawArc()` draws a full circle (360°) track, there is a visible seam artifact at the 0° position where the start and end points overlap.

## Root Cause

`drawArc()` always has a start/end point. When `cornerRadius > 0`:
- **With `Cap.ROUND`**: Two round caps overlap at 0°, creating a visible bump
- **With `drawRoundedBlock`**: Two rounded blocks overlap at the same position

The `ROUND_CAP_RAMP_DOWN` logic extends the arc beyond 360° to hide caps, but anti-aliasing still produces a visible rendering artifact at the seam.

https://github.com/user-attachments/assets/4fb64601-e2d7-4a72-bb3a-31bd461d12fc

## Expected Behavior

A full circle track should render as a perfect circle with no visible seam or artifact.

## Proposed Fix

When `arcDegree >= 360f` and the path is not wavy, use `canvas.drawOval()` instead of `canvas.drawArc()`. `drawOval` has no start/end point concept, so the seam artifact is eliminated entirely.

| | `drawArc` (current) | `drawOval` (proposed) |
|---|---|---|
| Start/end point | Exists (0° seam) | None |
| Cap needed | ROUND/BUTT + roundedBlock | Unnecessary (BUTT suffices) |
| 360° rendering | Cap overlap artifact | Perfect circle |

Partial arcs (indicators) continue to use the existing `drawArc` logic unchanged.

## Affected Component

`CircularDrawingDelegate.java` - `drawArc()` method

Start in CircularDrawingDelegate.java at the drawArc() method and trace how full-circle and partial-arc paths are rendered, including the non-wavy condition. Verify that full-circle tracks render without a seam while partial arcs retain their existing behavior; the issue's attached comparison illustrates the expected visual result.

Written by the indexing model from the issue text.