feat: add admin publishing workflow and yar theme

Add Go/Postgres admin APIs, Angular admin UI, manual build flow, asset uploads, markdown import/export, configurable slug generation, and the Yar reading theme. Exclude local docs and generated development artifacts from version control.

content/posts/pain.md

@@ -0,0 +1,19 @@
+---
+id: 501c6842-c113-48f4-8dc3-d53655918c38
+slug: pain
+title: 痛苦
+summary: ""
+status: published
+tags: []
+cover: ""
+version: 1
+slug_source: manual
+slug_locked: true
+published_at: "2026-01-07T09:26:42+08:00"
+created_at: "2025-01-16T11:13:00+08:00"
+updated_at: "2026-01-07T09:26:42+08:00"
+---
+
+事情一直没有结果，而努力被认定为理所当然，一旦犯下错误便被严加训责，脑子昏昏沉沉的，讨厌这个社会，讨厌身边的人，看得到头的生命，我明白自己是普通人，但是但是，我真的走不下去了，苟活着，三餐维持得了自己的生命。朝生暮死，何异于虫蝼，无非是稍久几年罢了……怎么会这样啊
+
+劳苦作兮终徒然，哀吾身兮悲且贱，信念几将殆。