test(format): redact plumb_version in JSON snapshots #375

Job	Run time
Preflight (fmt, clippy, check, agents-md)	56s
cargo-deny	43s
Determinism	51s
MSRV (1.95)	29s
Size guard (<25 MiB)	3m 15s
Test (windows-latest)	4m 31s
Test (macos-latest)	9m 3s
Test (ubuntu-latest)	2m 15s
Docs (build, no deploy)	48s
Coverage	6m 52s
	29m 43s

Provide feedback