Update Custom Modes video to new YouTube link

- Replace old video ID (qgqceCuhlRA) with new video ID (iiAv1eKOaxk)
- Updated in docs/index.md (homepage video grid)
- Updated in docs/features/custom-modes.mdx (embedded video)
- Updated in docs/tutorial-videos.json (tutorial videos sidebar)

Author: Sannidhya

docs/features/custom-modes.mdx

@@ -16,7 +16,7 @@ Roo Code allows you to create **custom modes** to tailor Roo's behavior to speci
 
 <div style={{ position: 'relative', paddingBottom: '56.25%', height: 0, overflow: 'hidden' }}>
   <iframe
-    src="https://www.youtube.com/embed/qgqceCuhlRA"
+    src="https://www.youtube.com/embed/iiAv1eKOaxk"
     style={{
       position: 'absolute',
       top: 0,

docs/index.md

@@ -47,8 +47,8 @@ Roo Code unleashes the full power of large language models inside VS Code. No du
     <img src="https://img.youtube.com/vi/r1bpod1VWhg/maxresdefault.jpg" alt="Codebase Indexing" style={{ width: '100%', height: 'auto', borderRadius: '8px', display: 'block' }} />
     <div style={{ marginTop: '0.0rem', textAlign: 'center', fontWeight: 600, fontSize: '1rem' }}>Codebase Indexing</div>
   </a>
-  <a href="https://www.youtube.com/watch?v=qgqceCuhlRA" target="_blank" rel="noopener noreferrer" style={{ textDecoration: 'none', color: 'inherit' }}>
-    <img src="https://img.youtube.com/vi/qgqceCuhlRA/maxresdefault.jpg" alt="Custom Modes" style={{ width: '100%', height: 'auto', borderRadius: '8px', display: 'block' }} />
+  <a href="https://youtu.be/iiAv1eKOaxk" target="_blank" rel="noopener noreferrer" style={{ textDecoration: 'none', color: 'inherit' }}>
+    <img src="https://img.youtube.com/vi/iiAv1eKOaxk/maxresdefault.jpg" alt="Custom Modes" style={{ width: '100%', height: 'auto', borderRadius: '8px', display: 'block' }} />
     <div style={{ marginTop: '0.0rem', textAlign: 'center', fontWeight: 600, fontSize: '1rem' }}>Custom Modes</div>
   </a>
   <a href="https://www.youtube.com/watch?v=Ho30nyY332E" target="_blank" rel="noopener noreferrer" style={{ textDecoration: 'none', color: 'inherit' }}>

docs/tutorial-videos.json

@@ -17,7 +17,7 @@
       "title": "Auto Approve Feature"
     },
     {
-      "id": "qgqceCuhlRA",
+      "id": "iiAv1eKOaxk",
       "title": "Custom Modes"
     },
     {