feat(uploads): an auto-language job is planned without the engines it never runs (#61)

PlanFor(lang) on the Ensemble and a LanguagePlanner the worker prefers: the page lists
the other engine (and the fallback if configured), not the base engine, the comparison and
the decisions as coming. Found by the PR #62 review.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/uploads/worker.go

@@ -33,6 +33,13 @@ type Transcriber interface {
 	Transcribe(ctx context.Context, wavPath string) (domain.Transcription, error)
 }
 
+// LanguagePlanner is a Planner whose phases depend on the language of the job: a recording
+// that is not Swedish skips the second engine and the reconcile, and the page should not list
+// them as coming (tapir#61). The worker prefers it over Planner.
+type LanguagePlanner interface {
+	PlanFor(lang domain.Language) []progress.Planned
+}
+
 // Planner is an optional extra on a Transcriber: it declares its own phases (for
 // example one per engine) so the page can show them. A Transcriber that does not
 // implement it gets a single "transcribing" phase from the worker. Whatever a Planner
@@ -251,8 +258,14 @@ func (w *Worker) Process(ctx context.Context, job Job) {
 	}
 
 	plan := []progress.Planned{{Key: "received", Label: "Received"}, {Key: "audio", Label: "Preparing the audio"}}
+	lang := job.Language
+	if lang == "" {
+		lang = domain.LangSwedish // queued before the choice existed
+	}
 	planner, planned := w.tr.(Planner)
-	if planned {
+	if lp, ok := w.tr.(LanguagePlanner); ok {
+		plan = append(plan, lp.PlanFor(lang)...)
+	} else if planned {
 		plan = append(plan, planner.Plan()...)
 	} else {
 		plan = append(plan, progress.Planned{Key: "transcribe", Label: "Transcribing"})
@@ -313,7 +326,7 @@ func (w *Worker) Process(ctx context.Context, job Job) {
 	if !planned {
 		tr.Begin("transcribe", 0)
 	}
-	t, err := w.tr.Transcribe(domain.WithLanguage(progress.With(jobCtx, tr), job.Language), wav)
+	t, err := w.tr.Transcribe(domain.WithLanguage(progress.With(jobCtx, tr), lang), wav)
 	if err != nil {
 		log.Error("upload: transcribe", "kind", errkind.Of(err), "elapsed", time.Since(start).Round(time.Second))
 		abort(domain.UploadErrTranscriptionFailed)