chore: 主题改媒体查询并清理未挂载 API

去掉 head 防闪脚本；删除论坛 JSON CRUD 与 crawler，仅保留机器入口；用户向文档对齐 SSR。

Co-authored-by: Cursor <cursoragent@cursor.com>

services/crawler.go

@@ -1,55 +0,0 @@
-package services
-
-import "strings"
-
-// 常见搜索引擎 / 社交预览 / SEO 工具的 User-Agent 片段（小写匹配）
-var seoCrawlerTokens = []string{
-	"googlebot",
-	"google-inspectiontool",
-	"bingbot",
-	"baiduspider",
-	"yandexbot",
-	"duckduckbot",
-	"slurp", // Yahoo
-	"sogou",
-	"bytespider",
-	"petalbot",
-	"applebot",
-	"facebookexternalhit",
-	"facebot",
-	"twitterbot",
-	"linkedinbot",
-	"discordbot",
-	"telegrambot",
-	"slackbot",
-	"whatsapp",
-	"preview", // 部分通用预览 UA
-	"embedly",
-	"quora link preview",
-	"pinterest",
-	"vkshare",
-	"w3c_validator",
-	"ahrefsbot",
-	"semrushbot",
-	"dotbot",
-	"mj12bot",
-	"gptbot",
-	"claudebot",
-	"anthropic-ai",
-	"chatgpt-user",
-	"oai-searchbot",
-}
-
-// IsSEOCrawler 是否为需要服务端 HTML 的爬虫 / 预览 bot（动态渲染）
-func IsSEOCrawler(userAgent string) bool {
-	ua := strings.ToLower(strings.TrimSpace(userAgent))
-	if ua == "" {
-		return false
-	}
-	for _, token := range seoCrawlerTokens {
-		if strings.Contains(ua, token) {
-			return true
-		}
-	}
-	return false
-}