chore: Alt description for dependency graph

Author: kamiazya

docs/ts-graphviz/11-advanced-topics/02-package-architecture.md

@@ -49,7 +49,7 @@ This approach allows you to manage dependencies in a way that best suits your pr
 
 The relationships between packages can be visualized as follows:
 
-![Dependency Graph](./img/dependency-graph.svg)
+![Package dependency graph showing relationships between ts-graphviz packages and their dependencies](./img/dependency-graph.svg)
 
 This modular architecture ensures:
 

i18n/ja/docusaurus-plugin-content-docs/current/ts-graphviz/11-advanced-topics/02-package-architecture.md

@@ -52,7 +52,7 @@ description: ts-graphvizのパッケージアーキテクチャ
 
 パッケージ間の関係は以下のように視覚化できます：
 
-![依存関係グラフ](./img/dependency-graph.svg)
+![ts-graphviz パッケージとその依存関係を示すパッケージ依存関係グラフ](./img/dependency-graph.svg)
 
 このモジュラーアーキテクチャにより、以下が確保されます：