fix: resolve crash on all commands due to missing @aws-sdk/region-config-resolver

[jesseturner21]

Summary

• @aws-cdk/toolkit-lib@1.25.2 depends on @aws-sdk/client-sts@^3, which now resolves to 3.1048.0. That version removed @aws-sdk/region-config-resolver from its dependencies, but toolkit-lib's bundled CJS still requires it — causing every agentcore command to crash on fresh install.
• Adds @aws-sdk/region-config-resolver as a direct dependency so it's always available.
• Adds early --version interception in the entrypoint to avoid loading heavy deps for version checks.

Test plan

• npm install -g . then agentcore --version prints version without error
• agentcore status --help loads without crash
• npm test passes

[github-actions]

Package Tarball

aws-agentcore-0.13.1.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-1276-tarball/aws-agentcore-0.13.1.tgz

[agentcore-cli-automation]

LGTM. The fix is small and correct: pulling @aws-sdk/region-config-resolver up to a direct dependency of @aws/agentcore ensures npm hoists it into top-level node_modules, where toolkit-lib's bundled CJS require('@aws-sdk/region-config-resolver') will resolve it after @aws-sdk/client-sts@3.1048.0 dropped it as a transitive dep.

I verified the root cause against the npm registry: @aws-sdk/client-sts@3.1047.0 lists @aws-sdk/region-config-resolver as a dependency, but 3.1048.0 (current latest) does not, while @aws-cdk/toolkit-lib's bundle still requires it.

Nice that the early --version short-circuit was dropped in 3b66758 — since src/cli/index.ts statically imports ./cli.js (which imports @aws-cdk/toolkit-lib transitively via cdk/toolkit-lib/wrapper.ts), ESM hoisting + esbuild bundling means those imports are evaluated before any top-level statement runs, so the short-circuit couldn't actually have avoided loading the heavy deps. Glad that's gone.

Two minor things worth mentioning (non-blocking, your call):

• The PR description still mentions the early --version interception that was removed — might be worth updating before merge so the commit history reflects what actually shipped.
• This is effectively a workaround for an upstream issue (toolkit-lib's bundle not declaring region-config-resolver as a direct dep). A short comment in package.json or a tracking issue link would help future maintainers know when it's safe to remove this direct dep.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	43.71%	9266 / 21196
🔵	Statements	42.97%	9837 / 22891
🔵	Functions	40.36%	1593 / 3946
🔵	Branches	40.49%	6043 / 14921

Generated in workflow #3028 for commit 3b66758 by the Vitest Coverage Report Action