added docs

src/app/docs/page.tsx

@@ -29,6 +29,7 @@ export default function Docs() {
     ids.  If no IDs are provided, all music will be returned.
 - \`/api/get_limit\`: Get quota Info
 - \`/api/extend_audio\`: Extend audio length
+- \`/api/concat\`: Generate the whole song from extensions
 \`\`\`
 
 Feel free to explore the detailed API parameters and conduct tests on this page.

src/app/page.tsx

@@ -106,6 +106,7 @@ Suno API currently mainly implements the following APIs:
 - \`/api/get?ids=\`: Get music Info by id, separate multiple id with ",".
 - \`/api/get_limit\`: Get quota Info
 - \`/api/extend_audio\`: Extend audio length
+- \`/api/concat\`: Generate the whole song from extensions
 \`\`\`
 
 For more detailed documentation, please check out the demo site: