go1.24: fix lint, unit and system tests

- development env: base on debian trixie with go1.24
- lint: run with default config
- fix lint errors
- fix unit tests
- fix system test

deb/package.go

@@ -565,7 +565,7 @@ func (p *Package) CalculateContents(packagePool aptly.PackagePool, progress aptl
 		}
 		return nil, err
 	}
-	defer reader.Close()
+	defer func() { _ = reader.Close() }()
 
 	contents, err := GetContentsFromDeb(reader, file.Filename)
 	if err != nil {