fix(transcribe): check (discard) the deferred Close errors golangci-lint flags

Found because the project's lint step cannot fail: the Taskfile runs
'golangci-lint run ./... || echo "not installed -- skipping"', so a failing lint
prints that message and exits 0. CI's log showed these findings and still passed.

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

internal/adapters/transcribe/gateway.go

@@ -62,7 +62,7 @@ func (g *Gateway) Transcribe(ctx context.Context, path string) (domain.Transcrip
 	if err != nil {
 		return domain.Transcription{}, fmt.Errorf("transcribe: open audio: %w", err)
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }()
 	info, err := f.Stat()
 	if err != nil {
 		return domain.Transcription{}, fmt.Errorf("transcribe: stat audio: %w", err)
@@ -95,7 +95,7 @@ func (g *Gateway) Transcribe(ctx context.Context, path string) (domain.Transcrip
 	if err != nil {
 		return domain.Transcription{}, fmt.Errorf("transcribe: %s: %w", g.model, err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode < 200 || resp.StatusCode > 299 {
 		snip, _ := io.ReadAll(io.LimitReader(resp.Body, 200))
 		return domain.Transcription{}, &StatusError{Code: resp.StatusCode, Snippet: strings.TrimSpace(string(snip))}