fix(lint): satisfy errcheck for io.Copy, json.Encode, Body.Close, deferred Close

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/session/session.go

@@ -73,7 +73,7 @@ func Read(sessionsDir, sessionID string) ([]Entry, error) {
 	if err != nil {
 		return nil, fmt.Errorf("open session log: %w", err)
 	}
-	defer f.Close()
+	defer f.Close() //nolint:errcheck
 
 	var entries []Entry
 	scanner := bufio.NewScanner(f)