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

controllers/admin_registry.go

@@ -14,7 +14,7 @@ import (
 )
 
 // PermissionManage is the one SEO permission (D-15): the SEO tab, URL
-// rules, settings and history.
+// rules, redirects, the 404 log, robots.txt, settings and history.
 const PermissionManage = "golem15.seo.manage"
 
 // The admin controller IDs.
@@ -29,6 +29,7 @@ const (
 func AdminControllers(app func() *backpack.App) []pact.AdminController {
 	return []pact.AdminController{
 		settingsAdminController{app: app},
+		redirectsAdminController{app: app},
 		rulesAdminController{app: app},
 		historyAdminController{app: app},
 	}

controllers/redirects.go

@@ -0,0 +1,192 @@
+package controllers
+
+import (
+	"context"
+	"strconv"
+
+	"git.golem15.com/golem15/sm-seo-plugin/classes"
+	"git.golem15.com/golem15/sm-seo-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"gorm.io/gorm"
+)
+
+// RedirectsControllerID is the redirects screen (UI-SPEC C8).
+const RedirectsControllerID = "golem15.seo.redirects"
+
+// redirectsAdminController lists and edits redirects (D-16 to D-19). The
+// loop refusal, the chain notice and history come from the plugin's own
+// field-less form extension on this controller, which runs inside the
+// save transaction once the row is written.
+type redirectsAdminController struct {
+	app func() *backpack.App
+}
+
+func (redirectsAdminController) ID() string        { return RedirectsControllerID }
+func (redirectsAdminController) ModelName() string { return `Golem15\SEO\Models\Redirect` }
+func (redirectsAdminController) ConfigDir() string { return "controllers/redirects" }
+func (redirectsAdminController) RequiredPermissions() []string {
+	return []string{PermissionManage}
+}
+
+// NewRecord is a redirect with the form's defaults, so a save that omits
+// an option keeps its default.
+func (redirectsAdminController) NewRecord() any {
+	r := models.NewRedirect()
+	return &r
+}
+
+// FormBeforeCreate normalises the redirect and refuses an invalid source,
+// target or regex, and a source and match another redirect has.
+func (c redirectsAdminController) FormBeforeCreate(ctx context.Context, model any) error {
+	return c.check(ctx, model)
+}
+
+// FormBeforeUpdate checks an update like a create.
+func (c redirectsAdminController) FormBeforeUpdate(ctx context.Context, model any) error {
+	return c.check(ctx, model)
+}
+
+func (c redirectsAdminController) check(ctx context.Context, model any) error {
+	r, ok := model.(*models.Redirect)
+	if !ok || r == nil {
+		return nil
+	}
+	r.Normalize()
+	db, err := database(ctx, c.app)
+	if err != nil {
+		return err
+	}
+	return problemsError(ctx, translator(c.app), r.Problems(db))
+}
+
+// FormAfterDelete records the deleted redirect in history inside the
+// delete's transaction.
+func (c redirectsAdminController) FormAfterDelete(ctx context.Context, model any) error {
+	r, ok := model.(*models.Redirect)
+	if !ok || r == nil {
+		return nil
+	}
+	svc, err := classes.NewService(appOf(c.app))
+	if err != nil {
+		return err
+	}
+	db, err := database(ctx, c.app)
+	if err != nil {
+		return err
+	}
+	return svc.Record(ctx, db, classes.Change{
+		Kind:      models.SubjectRedirect,
+		SubjectID: strconv.FormatUint(uint64(r.ID), 10),
+		What:      svc.Phrase("golem15.seo::lang.history.what_redirect", map[string]string{"url": r.Source}),
+		Before:    classes.RedirectValues(*r),
+	})
+}
+
+// ListRowStates marks a chain (UI-SPEC C8): a redirect whose target is
+// another redirect's source, labelled redirects.state_chain.
+func (redirectsAdminController) ListRowStates(ctx context.Context, db *gorm.DB, records []any) ([][]pact.RowState, error) {
+	var targets []string
+	for _, record := range records {
+		if r, ok := record.(*models.Redirect); ok && r != nil && r.Target != "" {
+			targets = append(targets, r.Target)
+		}
+	}
+	sources := map[string]bool{}
+	if len(targets) > 0 {
+		var rows []string
+		if err := db.WithContext(ctx).Model(&models.Redirect{}).Where("source IN ?", targets).Pluck("source", &rows).Error; err != nil {
+			return nil, err
+		}
+		for _, s := range rows {
+			sources[s] = true
+		}
+	}
+	out := make([][]pact.RowState, len(records))
+	for i, record := range records {
+		if r, ok := record.(*models.Redirect); ok && r != nil && r.Target != "" && sources[r.Target] {
+			out[i] = []pact.RowState{pact.RowStateNegative}
+		}
+	}
+	return out, nil
+}
+
+// matchLabels and originLabels are the phrase keys of the match kinds and
+// origins.
+var (
+	matchLabels = map[string]string{
+		models.RedirectExact:   "golem15.seo::lang.redirects.match_exact",
+		models.RedirectPattern: "golem15.seo::lang.redirects.match_pattern",
+		models.RedirectRegex:   "golem15.seo::lang.redirects.match_regex",
+	}
+	originLabels = map[string]string{
+		models.OriginManual:   "golem15.seo::lang.redirects.origin_manual",
+		models.OriginSlug:     "golem15.seo::lang.redirects.origin_slug",
+		models.OriginImport:   "golem15.seo::lang.redirects.origin_import",
+		models.OriginMCP:      "golem15.seo::lang.redirects.origin_mcp",
+		models.OriginNotFound: "golem15.seo::lang.redirects.origin_notfound",
+	}
+)
+
+// FilterOptions serves the choices of the status, match, origin and chain
+// filters.
+func (redirectsAdminController) FilterOptions(scope string) []pact.Option {
+	switch scope {
+	case models.FilterRedirectStatus:
+		return []pact.Option{
+			{Value: "301", Label: "golem15.seo::lang.redirects.status_301"},
+			{Value: "302", Label: "golem15.seo::lang.redirects.status_302"},
+			{Value: "410", Label: "golem15.seo::lang.redirects.status_410"},
+		}
+	case models.FilterRedirectMatch:
+		out := make([]pact.Option, 0, len(matchLabels))
+		for _, m := range []string{models.RedirectExact, models.RedirectPattern, models.RedirectRegex} {
+			out = append(out, pact.Option{Value: m, Label: matchLabels[m]})
+		}
+		return out
+	case models.FilterRedirectOrigin:
+		out := make([]pact.Option, 0, len(models.RedirectOrigins))
+		for _, o := range models.RedirectOrigins {
+			out = append(out, pact.Option{Value: o, Label: originLabels[o]})
+		}
+		return out
+	case models.FilterRedirectChain:
+		return []pact.Option{
+			{Value: models.ChainOnly, Label: "golem15.seo::lang.redirects.filter_chain_only"},
+			{Value: models.ChainHide, Label: "golem15.seo::lang.redirects.filter_chain_hide"},
+		}
+	}
+	return nil
+}
+
+// ListExtendRecords shows the match and the origin of the list's rows as
+// their labels in the request locale. The rows are list values only and
+// never saved; the columns still sort by the stored values.
+func (c redirectsAdminController) ListExtendRecords(ctx context.Context, _ *gorm.DB, records []any) error {
+	tr := translator(c.app)
+	for _, record := range records {
+		r, ok := record.(*models.Redirect)
+		if !ok || r == nil {
+			continue
+		}
+		if key, ok := matchLabels[r.Match]; ok {
+			r.Match = Phrase(ctx, tr, key, nil)
+		}
+		if key, ok := originLabels[r.Origin]; ok {
+			r.Origin = Phrase(ctx, tr, key, nil)
+		}
+	}
+	return nil
+}
+
+var (
+	_ pact.AdminController   = redirectsAdminController{}
+	_ pact.AdminPermissioned = redirectsAdminController{}
+	_ pact.AdminRecordSource = redirectsAdminController{}
+	_ pact.FormBeforeCreate  = redirectsAdminController{}
+	_ pact.FormBeforeUpdate  = redirectsAdminController{}
+	_ pact.FormAfterDelete   = redirectsAdminController{}
+	_ pact.ListRowStates     = redirectsAdminController{}
+	_ pact.FilterOptions     = redirectsAdminController{}
+	_ pact.ListExtendRecords = redirectsAdminController{}
+)

controllers/redirects/config_filter.yaml

@@ -0,0 +1,22 @@
+# Redirects filters (UI-SPEC C8): status, match, origin and chains.
+scopes:
+    status:
+        label: golem15.seo::lang.redirects.status
+        modelClass: Golem15\SEO\Models\Redirect
+        nameFrom: status
+        scope: FilterRedirectStatus
+    match:
+        label: golem15.seo::lang.redirects.match
+        modelClass: Golem15\SEO\Models\Redirect
+        nameFrom: match
+        scope: FilterRedirectMatch
+    origin:
+        label: golem15.seo::lang.redirects.origin
+        modelClass: Golem15\SEO\Models\Redirect
+        nameFrom: origin
+        scope: FilterRedirectOrigin
+    chain:
+        label: golem15.seo::lang.redirects.filter_chain
+        modelClass: Golem15\SEO\Models\Redirect
+        nameFrom: target
+        scope: FilterRedirectChain

controllers/redirects/config_form.yaml

@@ -0,0 +1,18 @@
+# Redirect form (UI-SPEC C8).
+name: golem15.seo::lang.redirects.name
+form: ~/plugins/golem15/seo/models/redirect/fields.yaml
+modelClass: Golem15\SEO\Models\Redirect
+defaultRedirect: golem15/seo/redirects
+
+create:
+    redirect: golem15/seo/redirects/update/:id
+    redirectClose: golem15/seo/redirects
+
+update:
+    redirect: golem15/seo/redirects
+    redirectClose: golem15/seo/redirects
+
+messages:
+    create: golem15.seo::lang.redirects.new
+    update: golem15.seo::lang.redirects.name
+    deleteConfirm: golem15.seo::lang.redirects.delete_confirm

controllers/redirects/config_list.yaml

@@ -0,0 +1,25 @@
+# Redirects list (UI-SPEC C8): newest change first, chains marked.
+list: ~/plugins/golem15/seo/models/redirect/columns.yaml
+modelClass: Golem15\SEO\Models\Redirect
+title: golem15.seo::lang.redirects.list_title
+recordUrl: golem15/seo/redirects/update/:id
+noRecordsMessage: golem15.seo::lang.redirects.list_empty
+recordsPerPage: 20
+showCheckboxes: true
+showSetup: true
+filter: config_filter.yaml
+
+defaultSort:
+    column: updated_at
+    direction: desc
+
+toolbar:
+    buttons: [create, delete]
+    search:
+        prompt: backend::lang.list.search_prompt
+
+messages:
+    create: golem15.seo::lang.redirects.new
+    empty: golem15.seo::lang.redirects.list_empty
+    deleteConfirm: golem15.seo::lang.redirects.delete_selected_confirm
+    rowStateNegative: golem15.seo::lang.redirects.state_chain