feat(app): add OrganizerLayout, PortalLayout, PublicLayout skeletons

WS-3 session 1a Task 2.

Three layout skeletons added to apps/app/src/layouts/. They are NOT
yet referenced by the router — that wiring is a later session.

- OrganizerLayout: thin wrapper around DefaultLayoutWithVerticalNav,
  visually identical to default.vue. Provides a semantically named
  target for future router meta:layout='OrganizerLayout'.
- PortalLayout: scaffold for volunteer/crew portal experience.
  Top bar + main + footer regions, no content yet.
- PublicLayout: minimal centered viewport for unauthenticated pages
  (login, password-reset, public form viewer).

default.vue and blank.vue are unchanged and remain the active layouts
referenced by the router. Their replacement happens in the router
consolidation session.

Refs: ARCH-CONSOLIDATION-2026-04.md §4 + §6.8.

apps/app/src/layouts/OrganizerLayout.vue

@@ -0,0 +1,9 @@
+<script setup lang="ts">
+import DefaultLayoutWithVerticalNav from '@/layouts/components/DefaultLayoutWithVerticalNav.vue'
+</script>
+
+<template>
+  <DefaultLayoutWithVerticalNav>
+    <RouterView />
+  </DefaultLayoutWithVerticalNav>
+</template>

apps/app/src/layouts/PortalLayout.vue

@@ -0,0 +1,32 @@
+<script setup lang="ts">
+// Portal layout skeleton — WS-3 session 1a.
+//
+// This is a foundation file. Content migration from apps/portal/ is a
+// later WS-3 session. The shape (top-bar / main / footer) is fixed
+// here so the router consolidation can target it with a stable name.
+//
+// DO NOT add nav, branding, or auth logic in this file directly.
+// Future sessions will compose those in via slots or child components.
+</script>
+
+<template>
+  <VApp>
+    <VAppBar
+      density="compact"
+      flat
+    >
+      <!-- Logo + portal nav land here in a later session -->
+    </VAppBar>
+
+    <VMain>
+      <RouterView />
+    </VMain>
+
+    <VFooter
+      app
+      class="text-caption"
+    >
+      <!-- Portal footer content lands here in a later session -->
+    </VFooter>
+  </VApp>
+</template>

apps/app/src/layouts/PublicLayout.vue

@@ -0,0 +1,16 @@
+<script setup lang="ts">
+// Public layout skeleton — WS-3 session 1a.
+//
+// Used for unauthenticated routes: login, password-reset, public
+// form viewer. Intentionally minimal — no nav, no branding chrome
+// in this skeleton. Branding (logo + responsive shell) lands in a
+// later session.
+</script>
+
+<template>
+  <VApp>
+    <VMain>
+      <RouterView />
+    </VMain>
+  </VApp>
+</template>