feat: 初始化 Astro 学习博客骨架

- Astro+TS 严格模式（禁止 any、显式返回类型）
- ESLint Flat Config + Prettier 格式化
- 内容集合（posts）与示例文章
- OSS 图床可配置 Img 组件
- 抽离 posts 数据逻辑（更易类型检查）
- getStaticPaths 修正（rest 路由传字符串）
- README/AGENTS 中文文档与约定
- Gitea CI：typecheck + lint
- 忽略 ref/（仅作临时参考）

package.json

@@ -0,0 +1,36 @@
+{
+  "name": "snowflake-notes",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "astro dev",
+    "build": "astro build",
+    "preview": "astro preview",
+    "lint": "eslint .",
+    "typecheck": "tsc -p tsconfig.json --noEmit",
+    "format": "prettier --write .",
+    "format:check": "prettier --check ."
+  },
+  "dependencies": {
+    "@astrojs/mdx": "^4.3.12",
+    "astro": "^5.16.1",
+    "zod": "^4.1.13"
+  },
+  "engines": {
+    "node": ">=20.0.0"
+  },
+  "packageManager": "pnpm@10.0.0+",
+  "devDependencies": {
+    "@types/node": "^24.10.1",
+    "@typescript-eslint/eslint-plugin": "^8.48.0",
+    "@typescript-eslint/parser": "^8.48.0",
+    "astro-eslint-parser": "^1.2.2",
+    "eslint": "^9.39.1",
+    "eslint-plugin-astro": "^1.5.0",
+    "prettier": "^3.6.2",
+    "prettier-plugin-astro": "^0.14.1",
+    "typescript": "^5.9.3",
+    "typescript-eslint": "^8.48.0"
+  }
+}