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/adapters/store/uploaded_transcripts_progress_test.go

@@ -20,7 +20,7 @@ import (
 func startedUpload(t *testing.T, s *store.Store) string {
 	t.Helper()
 	seedUsers(t, userA, userB)
-	id, err := s.CreateUpload(context.Background(), userA, "m", false)
+	id, err := s.CreateUpload(context.Background(), userA, "m", domain.LangSwedish, false)
 	require.NoError(t, err)
 	return id
 }