feat: add GovCloud multi-partition support

[aidandaly24]

Description

Adds multi-partition support to the AgentCore CLI, enabling deployment to GovCloud (us-gov-west-1) and laying groundwork for China (cn-*) regions.

Core change: New src/cli/aws/partition.ts utility module that maps AWS regions to partition-specific values (ARN prefix, DNS suffix, console domain). All hardcoded arn:aws:, amazonaws.com, and console.aws.amazon.com references in source files have been replaced with dynamic calls to this utility.

Changes

• New: src/cli/aws/partition.ts — central partition utility with getPartition, arnPrefix, dnsSuffix, serviceEndpoint, consoleDomain
• New: src/cli/aws/__tests__/partition.test.ts — 15 unit tests covering all 3 partitions × 5 functions
• ARN construction: 7 source files updated to use arnPrefix(region) instead of hardcoded arn:aws:
• ARN validation: 3 files updated — regex patterns now use arn:[^:]+: to accept any partition
• Endpoint URLs: 2 files updated to use serviceEndpoint() instead of hardcoded amazonaws.com
• Console URLs: trace-url.ts updated to use consoleDomain() for partition-correct CloudWatch deep links
• Region lists: us-gov-west-1 added to AgentCoreRegionSchema, BEDROCK_REGIONS, LLM compacted types, and tests
• CDK config: Added aws-us-gov to cdk.json target-partitions
• Static assets: execution-role-policy.json updated to use arn:*: partition wildcard for cross-partition IAM compatibility
• Documentation: Added "Multi-Partition Support" section to AGENTS.md with rules and checklists for adding new regions/partitions

Companion PR

• CDK constructs: https://github.com/aws/agentcore-l3-cdk-constructs/pull/ (will link after creation)

Supersedes

• add govcloud support #776 by @onchrs — this PR is a superset of that work with additional coverage (endpoint URLs, ARN regexes, console URLs, static assets, cdk.json, documentation)

Related Issue

Closes #

Documentation PR

None required — documentation added inline in AGENTS.md

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the
terms of your choice.

[github-actions]

Package Tarball

aws-agentcore-0.9.1.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-908-tarball/aws-agentcore-0.9.1.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	42.03%	7231 / 17202
🔵	Statements	41.44%	7664 / 18491
🔵	Functions	40.11%	1282 / 3196
🔵	Branches	40.5%	4824 / 11911

Generated in workflow #1897 for commit 9dd51f5 by the Vitest Coverage Report Action

[jariy17]

LGTM, just rebase if you can