fix: Jekyll設定をGitHub Pages標準構成に変更

- 複雑な依存関係を排除してシンプルな構成に
- theme: minima を使用
- GitHub Pages標準のgemのみ使用
- ビルド成功を優先した安定構成

docs/_config.yml

@@ -5,21 +5,13 @@ description: "外部ツールに依存せず、GitHub一つで開発業務を完
 url: "https://marketing-shibata50.github.io"
 baseurl: "/github-research-tool"
 
-# GitHub Pages settings
-remote_theme: "pages-themes/minimal@v0.2.0"
+# GitHub Pages settings - 標準的な設定に変更
+theme: minima
 plugins:
-  - jekyll-remote-theme
-  - jekyll-sitemap
   - jekyll-feed
+  - jekyll-sitemap
   - jekyll-seo-tag
 
-# Navigation
-header_pages:
-  - index.md
-  - features/01-repository-basics.md
-  - features/02-issues-management.md
-  - GITHUB_COMPLETE_GUIDE.md
-
 # GitHub repository
 github:
   repository_name: github-research-tool
@@ -37,35 +29,6 @@ kramdown:
   input: GFM
   syntax_highlighter: rouge
 
-# Include/Exclude files
-include:
-  - _pages
-  - assets
-
-exclude:
-  - vendor
-  - README.md
-  - Gemfile
-  - Gemfile.lock
-  - node_modules
-  - package.json
-
-# Collections
-collections:
-  guides:
-    output: true
-    permalink: /:collection/:name/
-  examples:
-    output: true
-    permalink: /:collection/:name/
-
 # SEO
 lang: ja
-timezone: Asia/Tokyo
-
-# Google Analytics (optional)
-# google_analytics: UA-XXXXXXXXX-X
-
-# Social
-social:
-  github: marketing-shibata50
+timezone: Asia/Tokyo