docs: retirer imports inutilisés de l'App.kt du plan

docs/superpowers/plans/2026-08-28-livrets-jeu-multiplications.md

@@ -1190,8 +1190,6 @@ git commit -m "feat: persistance de l'historique des parties en JSON (okio)"
 ```kotlin
 package com.livrets
 
-import androidx.compose.foundation.layout.WindowInsets
-import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf