encapsulate signer #9976

Job	Run time
Fuzz	14m 55s
Unit (macos-14)	7m 15s
Unit (ubuntu-20.04)	8m 9s
Unit (ubuntu-22.04)	7m 46s
e2e_post_etna	14m 2s
Unit (ubuntu-24.04)	8m 28s
Unit (windows-2022)	11m 37s
Unit (custom-arm64-jammy)	14m 26s
e2e_pre_etna	13m 9s
Unit (custom-arm64-noble)	14m 52s
Protobuf Lint	6s
e2e_existing_network	4m 35s
Lint	3m 54s
Upgrade	3m 40s
Up-to-date protobuf	21s
Up-to-date go.mod and go.sum	26s
Up-to-date mocks	1m 54s
Image build	10m 42s
Run bootstrap monitor e2e tests	6m 49s
Build Antithesis avalanchego images	10m 0s
Build Antithesis xsvm images	13m 23s
	2h 50m 29s

Provide feedback