feat(uploads): choose the language of a recording; record it, show it, carry it to the engines (#61)

Form field (Swedish preselected, Other = auto) read before the file part and refused
before anything is spooled if outside the closed set; stored on the row (migration 021,
CHECK constraint, default sv for history); carried on the Job and the worker's context;
shown on the status page. Feature scenarios and the coverage map are updated, and
ADR-033/034 amended.

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

internal/uploads/worker_test.go

@@ -126,6 +126,7 @@ type fakeTranscriber struct {
 	result domain.Transcription
 	err    error
 	paths  []string
+	langs  []domain.Language // what each call's context carried
 	// block, when non-nil, holds every call until it is closed or ctx ends.
 	block   chan struct{}
 	running atomic.Int32
@@ -134,6 +135,7 @@ type fakeTranscriber struct {
 
 func (f *fakeTranscriber) Transcribe(ctx context.Context, wav string) (domain.Transcription, error) {
 	f.paths = append(f.paths, wav)
+	f.langs = append(f.langs, domain.LanguageFrom(ctx))
 	n := f.running.Add(1)
 	defer f.running.Add(-1)
 	for {
@@ -337,3 +339,24 @@ func (dbErr) Error() string {
 	return `ERROR: invalid input syntax for type json: "zebrakaka secret words"`
 }
 func (dbErr) SQLState() string { return "22P02" }
+
+func TestWorker_TheTranscriberSeesTheLanguageOfTheJobOnItsContext(t *testing.T) {
+	for name, tt := range map[string]struct {
+		job  domain.Language
+		want domain.Language
+	}{
+		"auto":                   {domain.LangAuto, domain.LangAuto},
+		"swedish":                {domain.LangSwedish, domain.LangSwedish},
+		"a job with no language": {"", domain.LangSwedish}, // queued before the field existed
+	} {
+		t.Run(name, func(t *testing.T) {
+			r := newWRig(t, time.Minute)
+			job := r.spool(t, "a")
+			job.Language = tt.job
+
+			r.w.Process(context.Background(), job)
+
+			assert.Equal(t, []domain.Language{tt.want}, r.tr.langs)
+		})
+	}
+}