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/models/post.go

@@ -11,12 +11,13 @@ import (
 // Post is a blog post, the Go form of the WinterCMS Acme\Blog\Models\Post
 // model.
 type Post struct {
-	ID        uint      `gorm:"column:id;primaryKey"`
-	Title     string    `gorm:"column:title"`
-	Slug      string    `gorm:"column:slug"`
-	Body      string    `gorm:"column:body"`
-	CreatedAt time.Time `gorm:"column:created_at"`
-	UpdatedAt time.Time `gorm:"column:updated_at"`
+	ID          uint       `gorm:"column:id;primaryKey"`
+	Title       string     `gorm:"column:title"`
+	Slug        string     `gorm:"column:slug"`
+	Body        string     `gorm:"column:body"`
+	PublishedAt *time.Time `gorm:"column:published_at"`
+	CreatedAt   time.Time  `gorm:"column:created_at"`
+	UpdatedAt   time.Time  `gorm:"column:updated_at"`
 }
 
 // TableName keeps the WinterCMS table name.
@@ -26,6 +27,15 @@ func (Post) TableName() string { return "acme_blog_posts" }
 // set from a request.
 func (Post) Fillable() []string { return []string{"title", "slug", "body"} }
 
+// Rules is the Go form of $rules. The admin API checks them with
+// lagoon.Validate on every save; unique ignores the post being updated.
+func (Post) Rules() map[string]string {
+	return map[string]string{
+		"title": "required|max:255",
+		"slug":  "required|max:255|unique:acme_blog_posts",
+	}
+}
+
 // NewPost is the Go form of Post::make($input): it copies only the fillable
 // keys of input onto a new post and drops the rest, such as id.
 func NewPost(input map[string]any) (*Post, error) {