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/web/uploads_disconnect_handler_test.go

@@ -14,6 +14,8 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"git.d-ma.be/mathias/tapir/internal/domain"
 )
 
 // A client that hangs up in the middle of an upload is routine, not a server fault. The
@@ -85,7 +87,7 @@ func TestUploadPost_AClientThatHangsUpAnywhereInTheBodyIsLoggedAtInfoAndNeverAsA
 // context is cancelled, then Accept fails the way a read from a dead connection does.
 type goneMidAccept struct{ cancel context.CancelFunc }
 
-func (g goneMidAccept) Accept(context.Context, string, string, io.Reader) (string, error) {
+func (g goneMidAccept) Accept(context.Context, string, string, domain.Language, io.Reader) (string, error) {
 	g.cancel()
 	return "", fmt.Errorf("receive: %w", io.ErrClosedPipe)
 }