DUNGEONS-34: implement Webka local streaming app

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

frontend/app.vue

@@ -0,0 +1,53 @@
+<script setup lang="ts">
+const { locale } = useI18n();
+const session = useSessionStore();
+const theme = useCookie("webka_theme", { default: () => "dark" });
+const accent = useCookie("webka_accent", { default: () => "#c3f66b" });
+useHead({
+  htmlAttrs: { lang: locale, "data-theme": theme },
+  bodyAttrs: {
+    style: computed(
+      () =>
+        `--accent: ${/^#[a-f\d]{6}$/i.test(accent.value) ? accent.value : "#c3f66b"}`,
+    ),
+  },
+});
+let heartbeat: ReturnType<typeof setInterval>;
+onMounted(() => {
+  heartbeat = setInterval(async () => {
+    if (
+      session.user &&
+      document.visibilityState === "visible" &&
+      !(await session.refresh())
+    )
+      await navigateTo("/login");
+  }, 60000);
+});
+onBeforeUnmount(() => clearInterval(heartbeat));
+</script>
+<template>
+  <div class="app-shell">
+    <svg class="glass-filter" aria-hidden="true" width="0" height="0">
+      <defs>
+        <filter id="glass-lens" x="-5%" y="-5%" width="110%" height="110%">
+          <feTurbulence
+            type="fractalNoise"
+            baseFrequency="0.012 0.018"
+            numOctaves="2"
+            seed="8"
+            result="noise"
+          />
+          <feDisplacementMap
+            in="SourceGraphic"
+            in2="noise"
+            scale="3"
+            xChannelSelector="R"
+            yChannelSelector="G"
+          />
+        </filter>
+      </defs></svg
+    ><a class="skip-link" href="#main">{{ $t("common.skip") }}</a
+    ><GlassNavBar />
+    <main id="main"><NuxtPage /></main>
+  </div>
+</template>