feat: add default meta tags for SEO

- Implement default_meta_tags method in ApplicationHelper
- Refactor application layout to utilize default_meta_tags

This change improves SEO by centralizing the meta tags configuration. It
ensures consistent metadata across the application while reducing
repetition in the layout files.

app/helpers/application_helper.rb

@@ -25,4 +25,27 @@ module ApplicationHelper
   def current_user_is_admin?
     current_user&.admin?
   end
+
+  def default_meta_tags
+    {
+      site: "TodayAIWeather",
+      title: "TodayAIWeather",
+      description: "Experience weather through artistic AI visualization. Daily updated weather art for cities worldwide.",
+      keywords: "AI weather art, weather visualization, city weather, artificial intelligence",
+      separator: "—".html_safe,
+      reverse: true,
+      og: {
+        site_name: "TodayAIWeather",
+        type: "website",
+        keywords: "ai, ai web, ai art, ai weather, weather art, AI visualization, today ai weather",
+        url: request.original_url
+      },
+      alternate: {
+        "en" => url_for(locale: "en"),
+        "zh-CN" => url_for(locale: "zh-CN"),
+        "ja" => url_for(locale: "ja"),
+        "ko" => url_for(locale: "ko")
+      }
+    }
+  end
 end

app/views/layouts/application.html.erb

@@ -5,22 +5,7 @@
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <meta name="apple-mobile-web-app-capable" content="yes">
     <meta name="mobile-web-app-capable" content="yes">
-    <%= display_meta_tags(
-          site: 'TodayAIWeather',
-          reverse: true,
-          og: {
-            site_name: 'TodayAIWeather',
-            type: 'website',
-            keywords: "ai, ai web, ai art, ai weather, weather art, AI visualization, today ai weather",
-            url: request.original_url
-          },
-          alternate: {
-            "en" => url_for(locale: 'en'),
-            "zh-CN" => url_for(locale: 'zh-CN'),
-            "ja" => url_for(locale: 'ja'),
-            "ko" => url_for(locale: 'ko')
-          }
-        ) %>
+    <%= display_meta_tags(default_meta_tags) %>
     <%= csrf_meta_tags %>
     <%= csp_meta_tag %>