fix(sandbox): address SigV4 review findings — security, correctness, … #2194

Job	Run time
Resolve PR metadata	7s
build-cli / Resolve build plan	4s
build-supervisor	0s
build-gateway	0s
kubernetes-ha-e2e	0s
e2e	-1s
kubernetes-e2e	-1s
GPU E2E result	-1s
gpu-e2e	-1s
Kubernetes HA E2E result	-1s
Core E2E result	-1s
build-cli / Rust cli (amd64) / cli (amd64)	14m 16s
build-cli / Build ${{ inputs.component }} (${{ matrix.arch }})	-1s
build-cli / Merge ${{ inputs.component }} manifest	-1s
	14m 19s

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