feat: management API and an MCP tool per SEO admin operation

- /_seo/api/v1 routes for the effective SEO of a URL with sources and
  owner, URL rules, redirects (loops refused with redirect_loop), the
  404 log actions, robots.txt and its tester, settings and history
- the CMS-data issue report: missing and duplicate titles and
  descriptions, rules over records, redirect chains, canonicals to
  noindex or redirected addresses, noindex addresses robots.txt blocks
- 24 MCP tools on those routes (backend guard, golem15.seo.manage)
- AdminOperations maps every admin operation to its tool;
  TestEveryAdminOperationHasTool and TestMCPReadToolsAreGET guard drift
- robots.txt writes go through classes.SaveRobots from the admin too

controllers/api/auth.go

@@ -183,3 +183,57 @@ func write(ctx context.Context, svc *classes.Service, fn func(ctx context.Contex
 func read(ctx context.Context, svc *classes.Service) (*gorm.DB, error) {
 	return svc.DB(ctx)
 }
+
+// The page sizes of the list endpoints.
+const (
+	defaultPerPage = 50
+	maxPerPage     = 200
+)
+
+// ListInput is the paging and search query every list tool shares.
+type ListInput struct {
+	Page    int    `json:"page,omitempty" query:"page" jsonschema:"the page number, from 1"`
+	PerPage int    `json:"per_page,omitempty" query:"per_page" jsonschema:"rows per page, at most 200 (50 by default)"`
+	Search  string `json:"search,omitempty" query:"search" jsonschema:"text the address or value contains"`
+}
+
+// listParams reads page, per_page and search.
+func listParams(r *http.Request) ListInput {
+	q := r.URL.Query()
+	in := ListInput{Search: strings.TrimSpace(q.Get("search"))}
+	in.Page, _ = strconv.Atoi(q.Get("page"))
+	in.PerPage, _ = strconv.Atoi(q.Get("per_page"))
+	if in.Page < 1 {
+		in.Page = 1
+	}
+	if in.PerPage < 1 {
+		in.PerPage = defaultPerPage
+	}
+	if in.PerPage > maxPerPage {
+		in.PerPage = maxPerPage
+	}
+	return in
+}
+
+// paginate counts q and loads one page of it into dest.
+func paginate(q *gorm.DB, in ListInput, dest any) (int64, error) {
+	var total int64
+	if err := q.Session(&gorm.Session{}).Count(&total).Error; err != nil {
+		return 0, err
+	}
+	if err := q.Offset((in.Page - 1) * in.PerPage).Limit(in.PerPage).Find(dest).Error; err != nil {
+		return 0, err
+	}
+	return total, nil
+}
+
+// listBody is a list answer: the rows and the paging.
+func listBody(rows any, in ListInput, total int64) map[string]any {
+	return map[string]any{"data": rows, "page": in.Page, "per_page": in.PerPage, "total": total}
+}
+
+// like is a case-insensitive LIKE pattern of text.
+func like(text string) string {
+	r := strings.NewReplacer(`\`, `\\`, `%`, `\%`, `_`, `\_`)
+	return "%" + strings.ToLower(r.Replace(text)) + "%"
+}