feat(admin): post content on the Blog Editor field type

- blogeditor and mlblogeditor field types (classes.BlogEditorTypes) on the
  plugin; post content is mlblogeditor with htmlColumn content_html
- Decode stores SanitizeHTMLReport output per locale with notices naming
  what was removed; clean HTML is stored byte for byte, nothing is refused
  because of markup
- Load serves HTML as stored and markdown posts as their content_html
- the admin hooks copy written content to content_html per locale without
  goldmark; untouched content leaves both columns as they are
- editor lang keys (en, pl plural notices), tracer smoke test, updated
  Postgres admin tests

controllers/posts.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"strconv"
 
-	"git.golem15.com/golem15/sm-journal-plugin/classes"
 	"git.golem15.com/golem15/sm-journal-plugin/console"
 	"git.golem15.com/golem15/sm-journal-plugin/models"
 	"git.golem15.com/golem15/summercms/modules/backpack"
@@ -210,13 +209,75 @@ func preparePostWrite(ctx context.Context, post *models.Post) error {
 			"published_at": []string{"golem15.journal::lang.post.published_validation"},
 		}}
 	}
-	html, err := classes.FormatHTML(post.Content)
-	if err != nil {
-		return &cabana.ValidationError{Details: map[string]any{
-			"content": []string{err.Error()},
-		}}
+	// D-02: the Blog Editor's Decode already stored the policy's output in
+	// content; content_html gets the same HTML, without goldmark. Content the
+	// save does not write (untouched, D-03) leaves content_html as it is.
+	if writes, ok := cabana.FieldWritesFromContext(ctx); ok {
+		for _, w := range writes["content"] {
+			if !w.Default {
+				continue
+			}
+			if html, isString := w.Value.(string); isString {
+				post.ContentHTML = html
+			}
+		}
+	}
+	return nil
+}
+
+// FormAfterCreate writes content_html for every non-default locale whose
+// content the save wrote (D-02).
+func (c postsAdminController) FormAfterCreate(ctx context.Context, model any) error {
+	return c.writeContentHTMLTranslations(ctx, model)
+}
+
+// FormAfterUpdate writes content_html for every non-default locale whose
+// content the save wrote (D-02). Untouched locales are not listed and keep
+// their content_html.
+func (c postsAdminController) FormAfterUpdate(ctx context.Context, model any) error {
+	return c.writeContentHTMLTranslations(ctx, model)
+}
+
+// writeContentHTMLTranslations stores each written non-default content
+// value as that locale's content_html through the published
+// cabana.TranslationWriter, inside the save transaction. Without a writer
+// there is nothing to write.
+func (c postsAdminController) writeContentHTMLTranslations(ctx context.Context, model any) error {
+	post, ok := model.(*models.Post)
+	if !ok || post == nil {
+		return errors.New("posts admin: form model is not a post")
+	}
+	writes, ok := cabana.FieldWritesFromContext(ctx)
+	if !ok {
+		return nil
+	}
+	var pending []cabana.FieldWrite
+	for _, w := range writes["content"] {
+		if !w.Default && w.Locale != "" {
+			pending = append(pending, w)
+		}
+	}
+	if len(pending) == 0 {
+		return nil
+	}
+	app := c.application()
+	if app == nil {
+		return nil
+	}
+	writer, ok := app.Lookup[cabana.TranslationWriter]()
+	if !ok || writer == nil {
+		return nil
+	}
+	tx := c.db(ctx)
+	for _, w := range pending {
+		html, isString := w.Value.(string)
+		if !isString {
+			return fmt.Errorf("posts admin: content for %s is %T, want a string", w.Locale, w.Value)
+		}
+		if err := writer.WriteTranslated(ctx, tx, post, "content_html", w.Locale, html); err != nil {
+			return err
+		}
 	}
-	post.ContentHTML = html
 	return nil
 }