fix: tap anywhere outside attachment menu to dismiss it

app/src/main/java/dev/kaizen/app/chat/ChatScreen.kt

@@ -552,6 +552,18 @@ fun ChatScreen(
                             Spacer(Modifier.height(16.dp))
                         }
 
+                        // Dismiss scrim — tap anywhere to close the attachment menu
+                        if (showAttachMenu) {
+                            Box(
+                                Modifier
+                                    .fillMaxSize()
+                                    .clickable(
+                                        interactionSource = remember { androidx.compose.foundation.interaction.MutableInteractionSource() },
+                                        indication = null,
+                                    ) { showAttachMenu = false }
+                            )
+                        }
+
                         // Attachment menu — floats above the + button at bottom-left
                         androidx.compose.animation.AnimatedVisibility(
                             visible = showAttachMenu,