fix(docs): use preset color names for Progress.Circle in preview

Progress.Circle only supports preset names (primary, blue, green,
yellow, red) — not CSS variable strings. The var() values were
silently ignored, rendering circles without stroke color.

Author: wangdicoder

apps/docs/src/containers/theme-editor/components/preview-panel.tsx

@@ -164,8 +164,8 @@ export const PreviewPanel = (): React.ReactElement => {
         </Flex>
         <Flex gap="lg" style={{ marginTop: 16 }}>
           <Progress.Circle percent={75} width={80} />
-          <Progress.Circle percent={50} width={80} strokeColor="var(--ty-color-success)" />
-          <Progress.Circle percent={90} width={80} strokeColor="var(--ty-color-warning)" />
+          <Progress.Circle percent={50} width={80} strokeColor="green" />
+          <Progress.Circle percent={90} width={80} strokeColor="yellow" />
         </Flex>
         <Progress.Bar percent={65} style={{ marginTop: 12 }} />
       </section>