画面下部に必要なスペース関連の改善 (#9509)

* enhance: apply same safe area processing to the tab bar

* fix: remove unnecessary bottom space on messaging room

* enhance bottom spacing

* fix size of `minBottomSpacing`

packages/frontend/src/ui/_common_/stream-indicator.vue

@@ -38,8 +38,8 @@ onUnmounted(() => {
 .nsbbhtug {
 	position: fixed;
 	z-index: 16385;
-	bottom: 8px;
-	right: 8px;
+	bottom: calc(var(--minBottomSpacing) + var(--margin));
+	right: var(--margin);
 	margin: 0;
 	padding: 6px 12px;
 	font-size: 0.9em;