feat(agentsh): add agentsh execution-layer security Dev Container Feature #32

Job	Run time
shellcheck-agentsh	6s
test-global	53s
agentsh-rest-auth	25s
agentsh-shim-integration	39s
test-autogenerated (rust-dev-tools, mcr.microsoft.com/devcontainers/rust:latest)	10m 59s
test-autogenerated (modern-cli-tools, mcr.microsoft.com/devcontainers/base:ubuntu)	52s
test-autogenerated (ai-clis, mcr.microsoft.com/devcontainers/javascript-node:22)	1m 7s
test-autogenerated (python-tools, mcr.microsoft.com/devcontainers/python:latest)	2m 13s
agentsh-release-architecture (linux/amd64)	4s
agentsh-release-architecture (linux/arm64)	6s
test-scenarios (modern-cli-tools)	39s
test-autogenerated (node-dev-tools, mcr.microsoft.com/devcontainers/javascript-node:22)	1m 49s
test-scenarios (node-dev-tools)	1m 9s
test-scenarios (ai-clis)	1m 19s
test-scenarios (python-tools)	1m 22s
test-autogenerated (github-actions-tools, mcr.microsoft.com/devcontainers/base:ubuntu)	32s
test-scenarios (agentsh)	1m 59s
test-scenarios (github-actions-tools)	34s
test-scenarios (rust-dev-tools)	2m 55s
	29m 42s

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