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>

themes/minimal/pages/search.html

@@ -0,0 +1,2 @@
+<section class="pro-inner-hero"><div class="pro-wrap"><span class="pro-eyebrow">SEARCH / CONTENT</span><h1>站内搜索</h1><p>搜索本网站的产品、品牌、新闻和案例。</p></div></section>
+<main id="main-content" class="sf-search-page pro-wrap"><label for="sf-search">输入关键词</label><input type="search" id="sf-search" placeholder="搜索产品、品牌、新闻、案例……" autofocus><div id="sf-search-count" aria-live="polite"></div><div id="sf-search-results"></div></main>