DUNGEONS-34: implement Webka local streaming app

Co-authored-by: multica-agent <github@multica.ai>

frontend/components/LanguageSwitcher.vue

@@ -0,0 +1,46 @@
+<script setup lang="ts">
+import { Globe2, ChevronDown } from "lucide-vue-next";
+const { locale, setLocale } = useI18n();
+const open = ref(false);
+const root = ref<HTMLElement>();
+const languages = [
+  { code: "en", name: "English" },
+  { code: "ru", name: "Русский" },
+  { code: "es", name: "Español" },
+] as const;
+function outside(e: PointerEvent) {
+  if (!root.value?.contains(e.target as Node)) open.value = false;
+}
+onMounted(() => document.addEventListener("pointerdown", outside));
+onBeforeUnmount(() => document.removeEventListener("pointerdown", outside));
+</script>
+<template>
+  <div ref="root" class="language" @keydown.esc="open = false">
+    <GlassButton
+      :aria-label="$t('general.language')"
+      :aria-expanded="open"
+      aria-controls="language-options"
+      @click="open = !open"
+      ><Globe2 :size="17" /><span>{{ locale.toUpperCase() }}</span
+      ><ChevronDown :size="14"
+    /></GlassButton>
+    <GlassCard
+      v-if="open"
+      id="language-options"
+      class="language-menu"
+      role="group"
+      :aria-label="$t('general.language')"
+      ><button
+        v-for="lang in languages"
+        :key="lang.code"
+        :aria-pressed="locale === lang.code"
+        @click="
+          setLocale(lang.code);
+          open = false;
+        "
+      >
+        {{ lang.name }}<span v-if="locale === lang.code">✓</span>
+      </button></GlassCard
+    >
+  </div>
+</template>