feat: initial blog engine with multi-language, profile, and role system

- Gin + GORM + Tailwind CSS blog engine
- OS-aware config (Linux /etc/blog_go/, Windows ./win/etc/blog_go/)
- SQLite by default, MySQL support via config
- Auto-migrate database + seed admin user on first run
- Session-based auth (login/logout)
- i18n: Chinese/English with auto-detect + manual switch
- Avatar dropdown nav with click-to-toggle menu
- Profile page: avatar upload, edit info, change password
- Role system: admin (full access) and author (profile only)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

templates/pages/home.html

@@ -0,0 +1,38 @@
+{{define "home"}}
+{{template "header" .}}
+<section class="max-w-5xl mx-auto px-4 py-20 text-center">
+    <h1 class="text-5xl font-extrabold text-gray-900 mb-4">
+        {{index .Tr "home_welcome"}}
+    </h1>
+    <p class="text-xl text-gray-600 mb-8 max-w-2xl mx-auto">
+        {{index .Tr "home_subtitle"}}
+    </p>
+    <div class="flex justify-center gap-4">
+        <a href="/login" class="inline-block bg-blue-600 text-white px-6 py-3 rounded-lg font-medium hover:bg-blue-700 transition-colors">
+            {{index .Tr "home_sign_in"}}
+        </a>
+        <a href="/admin" class="inline-block bg-gray-200 text-gray-700 px-6 py-3 rounded-lg font-medium hover:bg-gray-300 transition-colors">
+            {{index .Tr "home_to_dash"}}
+        </a>
+    </div>
+</section>
+
+<section class="max-w-5xl mx-auto px-4 py-16">
+    <h2 class="text-3xl font-bold text-gray-900 mb-8 text-center">{{index .Tr "home_latest"}}</h2>
+    <div class="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
+        <div class="bg-white rounded-xl shadow-sm border border-gray-200 p-6">
+            <h3 class="text-lg font-semibold text-gray-800 mb-2">{{index .Tr "home_post1_tit"}}</h3>
+            <p class="text-gray-500 text-sm">{{index .Tr "home_post1_dsc"}}</p>
+        </div>
+        <div class="bg-white rounded-xl shadow-sm border border-gray-200 p-6">
+            <h3 class="text-lg font-semibold text-gray-800 mb-2">{{index .Tr "home_post2_tit"}}</h3>
+            <p class="text-gray-500 text-sm">{{index .Tr "home_post2_dsc"}}</p>
+        </div>
+        <div class="bg-white rounded-xl shadow-sm border border-gray-200 p-6">
+            <h3 class="text-lg font-semibold text-gray-800 mb-2">{{index .Tr "home_post3_tit"}}</h3>
+            <p class="text-gray-500 text-sm">{{index .Tr "home_post3_dsc"}}</p>
+        </div>
+    </div>
+</section>
+{{template "footer" .}}
+{{end}}