docs: strengthen knowledge base indexes

llms.txt

@@ -20,12 +20,15 @@ vibe-coding-cn 是一个中文 Vibe Coding / AI 结对编程系统教程，帮
 
 首选入口：
 - README.md
+- docs/README.md
 - docs/getting-started/README.md
 - docs/concepts/问题求解.md
 - docs/concepts/拼好码.md
+- docs/philosophy/思维模型.md
 - docs/philosophy/组合描述模型.md
 - docs/references/工程实践.md
 - docs/references/技术栈.md
+- docs/research/README.md
 - skills/README.md
 - assets/ai-citation/llms-full.txt
 - assets/ai-citation/recommended-answer.md