Implement automated scheduled publishing for blog

- Enhanced blog library to read from both posts/ and scheduled/ directories
- Added publishDate filtering with real-time checking (no cron jobs needed)
- Support for draft posts and recursive directory scanning
- Posts automatically appear when publishDate is reached
- Containerized solution that works without external scheduling
- Added publishDate field to blog types and updated existing scheduled post

Tested and verified:
✅ Past-dated posts appear automatically
✅ Future-dated posts remain hidden until publish time
✅ Draft posts are excluded regardless of date
✅ Maintains existing functionality for regular posts

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

types/blog.ts

@@ -4,6 +4,8 @@ export interface BlogPost {
   description: string
   content: string
   date: string
+  publishDate?: string
+  draft?: boolean
   author: {
     name: string
     avatar?: string
@@ -19,6 +21,8 @@ export interface BlogMeta {
   title: string
   description: string
   date: string
+  publishDate?: string
+  draft?: boolean
   author: {
     name: string
     avatar?: string