feat(12.1-01): declared bulk actions on admin lists

- pact.HasAdminBulkActions with AdminBulkAction, its input and result
- config_list.yaml bulkActions, compiled fail-loud, needs showCheckboxes
- POST .../{controller}/bulk/{action}: ids resolved and locked through the
  list scope in one transaction; partial selection is 409
- list schema offers declared actions per principal, with confirm text
- admin SPA bulk actions menu with confirm, busy state and failure toasts
- acme.roster fixture, tracer test, OpenAPI, TS types, dist, READMEs, docs

admin/tests/fixtures/roster.list-schema.json

@@ -0,0 +1,41 @@
+{
+  "data": {
+    "title": "People",
+    "recordsPerPage": 20,
+    "perPageOptions": [],
+    "showSearch": true,
+    "showSetup": false,
+    "showCheckboxes": true,
+    "showSorting": true,
+    "searchTerm": "search",
+    "recordUrl": "acme/roster/people/update/:id",
+    "toolbarButtons": ["create", "delete"],
+    "toolbarActions": [],
+    "assets": { "scripts": [], "styles": [] },
+    "columns": [
+      { "key": "name", "label": "Name", "searchable": true, "sortable": true },
+      { "key": "email", "label": "Email", "searchable": true, "sortable": true }
+    ],
+    "filters": [],
+    "rowActions": [],
+    "bulkActions": [
+      { "name": "delete", "label": "Delete selected" },
+      { "name": "activate", "label": "Activate", "confirm": "Activate the selected people?" },
+      { "name": "archive", "label": "Archive" }
+    ],
+    "messages": {
+      "create": { "other": "New person" },
+      "deleteConfirm": { "other": "Delete the selected (:count)?" },
+      "deleteSelected": { "other": "Delete selected" },
+      "deleted": { "one": "Deleted :count record", "other": "Deleted :count records" },
+      "empty": { "other": "There are no records in this view." },
+      "emptySearch": { "other": "Nothing found" },
+      "emptySearchHint": { "other": "No record matches “:term”. Try another search." },
+      "recordCount": { "one": ":count record", "other": ":count records" },
+      "searchPrompt": { "other": "Search…" },
+      "selected": { "other": ":count selected" }
+    },
+    "meta": { "locale": "en" }
+  },
+  "meta": { "locale": "en" }
+}