refactor: Gitea 式目录改组，移除本分支 SPA 与杂项产物

将 model/service/handler/middleware 迁至 models/services/routers/api/modules/auth，并删除 frontend、embed_static、scripts 及误入库缓存/二进制。

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

services/friend_link_reciprocal_test.go

@@ -0,0 +1,46 @@
+package service
+
+import (
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestPageContainsLinkToHost(t *testing.T) {
+	our, err := url.Parse("https://forum.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	page := "https://friend.example/links.html"
+	host := "forum.example.com"
+
+	if !pageContainsLinkToHost(`<a href="https://forum.example.com/">本站</a>`, page, our, host) {
+		t.Fatal("应检测到绝对回链")
+	}
+	if pageContainsLinkToHost(`<a href="https://other.example/">其他</a>`, page, our, host) {
+		t.Fatal("不应把外站当成回链")
+	}
+}
+
+func TestPageContainsLinkToHost_LargeHTMLFast(t *testing.T) {
+	our, err := url.Parse("https://forum.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var b strings.Builder
+	b.Grow(512 * 1024)
+	for b.Len() < 400*1024 {
+		b.WriteString(`<a href="https://noise.example/page">x</a>`)
+	}
+	b.WriteString(`<a href="https://forum.example.com/">本站</a>`)
+	html := b.String()
+
+	start := time.Now()
+	if !pageContainsLinkToHost(html, "https://friend.example/", our, "forum.example.com") {
+		t.Fatal("应在大量无关链接中找到回链")
+	}
+	if elapsed := time.Since(start); elapsed > 500*time.Millisecond {
+		t.Fatalf("解析耗时过长: %s", elapsed)
+	}
+}