fix: update MongoDB version requirements in documentation

CLAUDE.md

@@ -70,7 +70,7 @@ GROWI is a team collaboration software using markdown - a wiki platform with hie
 ### Development Dependencies
 - Node.js v20.x or v22.x
 - pnpm 10.x  
-- MongoDB 8.0+
+- MongoDB v6.x or v8.x
 - Optional: Redis 3.x, Elasticsearch 7.x/8.x/9.x (for full-text search)
 
 ## File Organization Patterns

README.md

@@ -85,7 +85,7 @@ See [GROWI Docs: Environment Variables](https://docs.growi.org/en/admin-guide/ad
 - npm 10.x
 - pnpm 10.x
 - [Turborepo](https://turbo.build/repo)
-- MongoDB 8.0 or above
+- MongoDB v6.x or v8.x
 
 ### Optional Dependencies
 

README_JP.md

@@ -85,7 +85,7 @@ Crowi からの移行は **[こちら](https://docs.growi.org/en/admin-guide/mig
 - npm 10.x
 - pnpm 10.x
 - [Turborepo](https://turbo.build/repo)
-- MongoDB 8.0 以上
+- MongoDB v6.x or v8.x
 
 ### オプションの依存関係