feat: add document templates library with 10 templates

src/templates/blog-post.md

@@ -0,0 +1,20 @@
+---
+title: Blog Post Title
+date: {{DATE}}
+author: Your Name
+tags: []
+---
+
+# Blog Post Title
+
+## Introduction
+
+Write your introduction here.
+
+## Main Content
+
+Your main content goes here.
+
+## Conclusion
+
+Wrap up your thoughts.