fix(practice): remove overflow clipping to allow help overlays

Remove overflow-x/overflow-y clipping as CSS doesn't allow mixing
visible and hidden on different axes. The outgoing problem fades
to opacity 0 anyway so clipping isn't needed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/components/practice/ActiveSession.tsx

@@ -981,8 +981,7 @@ export function ActiveSession({
             display: 'flex',
             justifyContent: 'center',
             width: '100%',
-            overflowX: 'hidden', // Clip horizontal transition, allow vertical for help overlays
-            overflowY: 'visible',
+            // No overflow clipping - outgoing problem fades to opacity 0 anyway
           })}
         >
           {/* Animated track for problem transitions */}