chore: import SiteForge Factory V5 source (baseline)

导入 SiteForge Factory V5 基线源码：
- FastAPI + SQLite + Docker Compose（Web + Worker）架构
- 四套商业主题 × 14 页面模板（1.1.0，含历史版本快照）
- 四种建站模式骨架 + 迁移审计 + 发布门禁
- 52 项 pytest 测试
- 补全计划主文档 docs/superpowers/plans/

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

examples/content.json

@@ -0,0 +1,20 @@
+{
+  "entries": [
+    {
+      "type": "page",
+      "title": "About Us",
+      "route": "/about-us/",
+      "summary": "Learn more about our global business.",
+      "body": "<h2>Who we are</h2><p>Replace this example content with your real company introduction.</p>",
+      "seo_title": "About Us",
+      "seo_description": "Our company introduction."
+    },
+    {
+      "type": "service",
+      "title": "Global Shipping",
+      "route": "/services/global-shipping/",
+      "summary": "Integrated shipping and delivery coordination.",
+      "body": "<p>Describe your real shipping services here.</p>"
+    }
+  ]
+}