add Just Dance by Lady Gaga as second song

Simfile from zenius-i-vanisher.com (iamthek3n Selections).
119 BPM, 2:05 duration, Beginner through Hard difficulties.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -27,6 +27,11 @@ Webcam pose detection app using MediaPipe Tasks Vision. Vite + React 19 + TypeSc
 - Site: https://hackhackrevolution.xyz
 - Vercel project: `project-zcx72` under `jorqsrazes-projects`
 
+## Song Sources
+
+- Fraxtil's Beast Beats [SM5] — 20 songs bundled with the game
+- Just Dance (Lady Gaga) — simfile from https://zenius-i-vanisher.com/v5.2/viewsimfile.php?simfileid=35263
+
 ## Code guidelines
 
 - **Modular architecture**: each file should have a single, clear responsibility. Extract logic into separate modules rather than growing large files.

src/features/song-select/song-data.ts

@@ -15,6 +15,20 @@ export const SONGS: Song[] = [
     bgUrl: '/songs/get-lucky/bg.png',
     bannerUrl: '/songs/get-lucky/bn.png',
   },
+  {
+    id: 'just-dance',
+    title: 'Just Dance',
+    artist: 'Lady Gaga ft. Colby O\'Donis',
+    bpm: 119,
+    difficulty: 3,
+    duration: '2:05',
+    genre: 'Pop',
+    color: '#E91E63',
+    chartUrl: '/songs/just-dance/chart.ssc',
+    audioUrl: '/songs/just-dance/audio.ogg',
+    bgUrl: '/songs/just-dance/bg.png',
+    bannerUrl: '/songs/just-dance/bn.png',
+  },
   {
     id: 'axion',
     title: 'Axion',