feat(11.1-05): add the walkthrough's admin controller, publish command and published_at migration

- make:admin-controller, make:command and make:migration output, finished:
  the Posts controller serves models.Post behind acme.blog.access_posts,
  WinterCMS-style form and list YAML embedded through pact.AdminAssets,
  blog:publish sets published_at by slug with a bound parameter
- the posts route lists published posts only, newest first
- Docker tests migrate an ICU pl-PL database, roll back published_at, serve
  the route and run blog:publish with a published and an opened database
- the page gains the admin controller, console command and added-column
  sections

docs/examples/blog/updates/20260101000100_add_published_at.go

@@ -0,0 +1,21 @@
+// Code generated by summer make. DO NOT EDIT.
+
+package updates
+
+import (
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+// AddPublishedAt returns the 20260101000100_add_published_at gormigrate entry.
+func AddPublishedAt() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "20260101000100_add_published_at",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.Exec("ALTER TABLE acme_blog_posts ADD COLUMN published_at TIMESTAMPTZ NULL").Error
+		},
+		Rollback: func(tx *gorm.DB) error {
+			return tx.Exec("ALTER TABLE acme_blog_posts DROP COLUMN IF EXISTS published_at").Error
+		},
+	}
+}