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>

cmd/tapir/uploads_test.go

@@ -25,7 +25,7 @@ type fakeUploadsStore struct {
 	failedKinds []domain.UploadErrorKind
 }
 
-func (f *fakeUploadsStore) CreateUpload(context.Context, string, string, bool) (string, error) {
+func (f *fakeUploadsStore) CreateUpload(context.Context, string, string, domain.Language, bool) (string, error) {
 	return "id", nil
 }