feat: Implement session management and routing for general creation

- Added session initialization in main.ts to manage user sessions.
- Updated router to include a new route for joining or creating a general.
- Enhanced session store with methods for managing session tokens and user profiles.
- Introduced new components for displaying city, general, nation, and command information.
- Implemented loading states and error handling in the main view.
- Created a skeleton loader component for better user experience during data fetching.
- Updated TypeScript definitions for route metadata to include new authentication requirements.

app/game-frontend/src/views/JoinView.vue

@@ -0,0 +1,10 @@
+<script setup lang="ts"></script>
+
+<template>
+    <main class="min-h-screen px-6 py-8">
+        <h1 class="text-2xl font-semibold">Create or Possess General</h1>
+        <p class="mt-2 text-sm text-amber-200/80">
+            You are logged in but do not have a playable general yet.
+        </p>
+    </main>
+</template>