feat: redirects screen

- golem15.seo.redirects list and form (UI-SPEC C8): chain rows marked,
  status, match, origin and chain filters, the navigation item lands here
- a field-less extension on the controller refuses a loop with
  redirects.loop on target, answers the chain notice and records history
- the status dropdown posts text, read through RedirectStatus

admin_navigation.go

@@ -6,8 +6,8 @@ import (
 )
 
 // Navigation registers the SEO main item (UI-SPEC C2) behind
-// golem15.seo.manage. It lands on URL rules until the redirects screen
-// exists; each side-menu entry is added when its controller exists.
+// golem15.seo.manage. It lands on Redirects; each side-menu entry is added
+// when its controller exists, in the C2 order.
 func (*Plugin) Navigation() []pact.NavigationItem {
 	return []pact.NavigationItem{{
 		Code:        "seo",
@@ -15,8 +15,15 @@ func (*Plugin) Navigation() []pact.NavigationItem {
 		Icon:        "search",
 		Permissions: []string{controllers.PermissionManage},
 		Order:       600,
-		Controller:  controllers.RulesControllerID,
+		Controller:  controllers.RedirectsControllerID,
 		SideMenu: []pact.NavigationItem{
+			{
+				Code:        "redirects",
+				Label:       "golem15.seo::lang.nav.redirects",
+				Icon:        "arrow-right",
+				Permissions: []string{controllers.PermissionManage},
+				Controller:  controllers.RedirectsControllerID,
+			},
 			{
 				Code:        "rules",
 				Label:       "golem15.seo::lang.nav.rules",