Initialize blog scaffold

Add the CLI, site, and sample content so the project can run locally.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/site/src/lib/siteConfig.ts

@@ -0,0 +1,60 @@
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, resolve } from 'node:path';
+import YAML from 'yaml';
+
+const siteRoot = resolve(dirname(fileURLToPath(import.meta.url)), '../../../..');
+
+type SiteConfig = {
+  site: {
+    title: string;
+    description: string;
+    base_url: string;
+    language: string;
+    timezone: string;
+  };
+  content: {
+    posts_dir: string;
+    assets_dir: string;
+  };
+  build: {
+    astro_project: string;
+    output_dir: string;
+  };
+};
+
+const defaults: SiteConfig = {
+  site: {
+    title: 'Osaet',
+    description: 'Personal blog',
+    base_url: 'http://localhost:4321',
+    language: 'zh-CN',
+    timezone: 'Asia/Shanghai'
+  },
+  content: {
+    posts_dir: 'content/posts',
+    assets_dir: 'content/assets'
+  },
+  build: {
+    astro_project: 'frontend/site',
+    output_dir: 'dist/site'
+  }
+};
+
+function loadSiteConfig(): SiteConfig {
+  try {
+    const file = readFileSync(resolve(siteRoot, 'config/site.yaml'), 'utf8');
+    const parsed = YAML.parse(file) ?? {};
+
+    return {
+      site: { ...defaults.site, ...parsed.site },
+      content: { ...defaults.content, ...parsed.content },
+      build: { ...defaults.build, ...parsed.build }
+    };
+  } catch {
+    return defaults;
+  }
+}
+
+export const siteConfig = loadSiteConfig();
+export const site = siteConfig.site;