feat: page registry with its admin screen and signpost type

- golem15_seo_pages (migration 202610280002): the site's own frontend pages
  with an address and a name per locale, kind, origin, parent, content date
  and note; settings routes_reported_at
- SEO > Pages (golem15.seo.pages) after URL rules: list with kind, origin
  and missing filters and the missing row state, form with the P9 partial;
  the plugin's form extension saves the address and name per locale and
  refuses url_required, url_invalid, url_taken and url_owned
- menu item type seo-page with a content descriptor, so each page gets
  the SEO tab, resolves ok and is listed in the sitemaps grouped by kind
  (pages, offers, services, landing-pages, titled per locale)
- management API GET/POST /_seo/api/v1/pages, PUT/DELETE /pages/{id} and
  the MCP tools seo_list_pages, seo_create_page, seo_update_page,
  seo_delete_page (in this commit because the operations parity test maps
  every Pages operation to its tool)

controllers/pages/_page_status.htm

@@ -0,0 +1,7 @@
+{{- with .Data -}}
+{{- if .Text -}}
+<div class="summer-callout{{ if .Warning }} summer-callout--warning{{ end }}" role="status">
+<p class="summer-callout__text">{{ .Text }}</p>
+</div>
+{{- end -}}
+{{- end -}}

controllers/pages/config_filter.yaml

@@ -0,0 +1,18 @@
+# Pages filters (UI-SPEC C21): kind, origin and missing from the newest
+# route report.
+scopes:
+    kind:
+        label: golem15.seo::lang.pages.kind
+        modelClass: Golem15\SEO\Models\Page
+        nameFrom: kind
+        scope: FilterPageKind
+    origin:
+        label: golem15.seo::lang.pages.origin
+        modelClass: Golem15\SEO\Models\Page
+        nameFrom: origin
+        scope: FilterPageOrigin
+    missing:
+        label: golem15.seo::lang.pages.filter_missing
+        modelClass: Golem15\SEO\Models\Page
+        nameFrom: url
+        scope: FilterPageMissing

controllers/pages/config_form.yaml

@@ -0,0 +1,20 @@
+# Page form (UI-SPEC C21). The address and the name per locale come from
+# the plugin's own form extension on this controller; the SEO tab is added
+# because the registry is a content type (seo-page).
+name: golem15.seo::lang.pages.name
+form: ~/plugins/golem15/seo/models/page/fields.yaml
+modelClass: Golem15\SEO\Models\Page
+defaultRedirect: golem15/seo/pages
+
+create:
+    redirect: golem15/seo/pages/update/:id
+    redirectClose: golem15/seo/pages
+
+update:
+    redirect: golem15/seo/pages
+    redirectClose: golem15/seo/pages
+
+messages:
+    create: golem15.seo::lang.pages.new
+    update: golem15.seo::lang.pages.name
+    deleteConfirm: golem15.seo::lang.pages.delete_confirm

controllers/pages/config_list.yaml

@@ -0,0 +1,26 @@
+# Pages list (UI-SPEC C21): the page registry by address; reported pages
+# missing from the newest route report are marked.
+list: ~/plugins/golem15/seo/models/page/columns.yaml
+modelClass: Golem15\SEO\Models\Page
+title: golem15.seo::lang.pages.list_title
+recordUrl: golem15/seo/pages/update/:id
+noRecordsMessage: golem15.seo::lang.pages.list_empty
+recordsPerPage: 20
+showCheckboxes: true
+showSetup: true
+filter: config_filter.yaml
+
+defaultSort:
+    column: url
+    direction: asc
+
+toolbar:
+    buttons: [create, delete]
+    search:
+        prompt: backend::lang.list.search_prompt
+
+messages:
+    create: golem15.seo::lang.pages.new
+    empty: golem15.seo::lang.pages.list_empty
+    deleteConfirm: golem15.seo::lang.pages.delete_selected_confirm
+    rowStateNegative: golem15.seo::lang.pages.state_missing