feat: journal:fix-headings and the settings API

- classes.FixStoredHeadings converts stored H1 in post content (every
  locale) and category pillar text, in one transaction with a RecordSaved
  and a site cache purge per changed record
- journal:fix-headings, a dry run unless --apply, refuses with exit code 1
  while the H1 setting is off
- GET/PUT /_journal/api/v1/settings and POST /fix-headings {dry_run} for
  golem15.journal.manage_settings; 409 with the refusal while the setting
  is off

console/fix_headings.go

@@ -0,0 +1,66 @@
+package console
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"git.golem15.com/golem15/sm-journal-plugin/classes"
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/bonfire"
+)
+
+// FixHeadings is journal:fix-headings: it converts H1 to H2 in stored
+// Journal rich text (post content in every locale and category pillar text)
+// while the Journal H1 setting is on. It is a dry run unless --apply is
+// given; with the setting off it refuses with exit code 1.
+func FixHeadings(app *backpack.App) bonfire.Command {
+	return bonfire.Command{
+		Name:        "journal:fix-headings",
+		Description: "Convert H1 headings to H2 in stored post and category content",
+		Long: `Finds every H1 heading in stored Journal content: post content and
+content_html in the default locale and in every translation, and the pillar
+text of every category. Switching the Journal H1 setting (Settings › Journal,
+Headings and links) on never rewrites stored content; this command does.
+
+By default it only counts ("Would convert N H1 headings in N posts and N
+categories. Run with --apply to save."). With --apply it converts them in
+one transaction, fires a record event per changed post and category (so an
+SEO or search plugin hears about it) and queues the site cache purge.
+
+While the H1 setting is off the command refuses and exits with code 1. The
+MCP tool journal_fix_headings runs the same conversion.`,
+		Flags: []bonfire.Flag{
+			{Name: "apply", Description: "Save the converted content (default: dry run)", Bare: true},
+			{Name: "dry-run", Description: "Only count the H1 headings (the default)", Bare: true},
+		},
+		Examples: []bonfire.Example{
+			{Command: "journal:fix-headings", Description: "Count the H1 headings that would be converted"},
+			{Command: "journal:fix-headings --apply", Description: "Convert them and save"},
+		},
+		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
+			db := mustDB(app)
+			if db == nil {
+				return errors.New("journal: database is not configured")
+			}
+			if !classes.EffectiveH1ToH2(ctx, db, appConfig(app)) {
+				out.Error(classes.H1ConversionOffText)
+				return bonfire.Reported(classes.ErrH1ConversionOff)
+			}
+			apply := flagOn(in, "apply") && !flagOn(in, "dry-run")
+			res, err := classes.FixStoredHeadings(ctx, app, db, apply)
+			if err != nil {
+				return err
+			}
+			switch {
+			case res.Headings == 0:
+				out.Info("No H1 headings found in post or category content.")
+			case apply:
+				out.Success(fmt.Sprintf("Converted %d H1 headings in %d posts and %d categories.", res.Headings, res.Posts, res.Categories))
+			default:
+				out.Info(fmt.Sprintf("Would convert %d H1 headings in %d posts and %d categories. Run with --apply to save.", res.Headings, res.Posts, res.Categories))
+			}
+			return nil
+		},
+	}
+}