sigs.k8s.io/yaml Marshal: U+0085 becomes a space, DEL/C1 chars error

sigs.k8s.io/yaml (v1.6.0, master too) implements Marshal as json.Marshal followed by JSONToYAML, and JSONToYAML parses the JSON text with go-yaml v2, which is YAML 1.1. Go's encoding/json leaves U+0085 (NEL), DEL, C1 controls (U+0080-U+009F) and U+FFFE/U+FFFF raw inside strings. YAML 1.1 treats NEL as a line break, so Marshal(map[string]string{"k": "a\u0085b"}) silently returns k: a b. The others are non-printable in YAML, so Marshal returns 'yaml: control characters are not allowed' for a perfectly valid Go string. go.yaml.in/yaml/v2's own Marshal escapes these correctly ("a\Nb", "a\x7Fb"). Fix: rewrite those runes as \uXXXX in the JSON before the yaml.Unmarshal in JSONToYAML. That's safe because outside strings valid JSON is plain ASCII. Workaround for callers: marshal with go.yaml.in/yaml/v2 or v3 directly when strings may contain arbitrary Unicode. Separately, JSONToYAML fails for any object key longer than 1024 chars (YAML implicit-key limit).