feat: Implement blog and blog post models, routes, and services

- Added Blog and BlogPost models with necessary fields and relationships.
- Created blogRouter for handling blog-related API endpoints including CRUD operations.
- Developed BlogService for business logic related to blogs and posts, including sharing functionality.
- Implemented API client methods for frontend to interact with blog-related endpoints.
- Added internationalization support for blog-related text in English and German.
- Created Vue components for blog editing, listing, and viewing, including a rich text editor for post content.
- Enhanced user experience with form validations and dynamic visibility settings based on user input.

frontend/src/views/blog/BlogListView.vue

@@ -0,0 +1,29 @@
+<template>
+  <div class="blog-list">
+    <h1>Blogs</h1>
+    <div class="toolbar">
+      <router-link v-if="$store.getters.isLoggedIn" class="btn" to="/blogs/create">Neuen Blog erstellen</router-link>
+    </div>
+    <div v-if="loading">Laden…</div>
+    <div v-else>
+      <div v-if="!blogs.length">Keine Blogs gefunden.</div>
+      <ul>
+        <li v-for="b in blogs" :key="b.id">
+          <router-link :to="`/blogs/${b.id}`">{{ b.title }}</router-link>
+          <small> – {{ b.owner?.username }}</small>
+        </li>
+      </ul>
+    </div>
+  </div>
+</template>
+
+<script>
+import { listBlogs } from '@/api/blogApi.js';
+export default {
+  name: 'BlogListView',
+  data: () => ({ blogs: [], loading: true }),
+  async mounted() {
+    try { this.blogs = await listBlogs(); } finally { this.loading = false; }
+  }
+}
+</script>