[notgitika]

Description

Addresses the remaining actionable review feedback from #2575 while keeping the compatibility layer small.

• delegate v0 deployment through the latest v0 release (@aws/agentcore@0) instead of pinning one patch version
• forward the v1-resolved AWS region to delegated v0 deployment, including first deploy with no targets configured
• omit toolRuntimes when v0 explicitly contains an empty mcpRuntimeTools array
• remove the duplicate LegacyExtras copy; legacy.v0Spec remains the source of truth for v0-only collections

Targeted replacement guidance for removed v0 commands is intentionally excluded until the wording is agreed.

Related Issue

Closes #2592

Documentation PR

Not applicable; this tightens internal compatibility behavior without adding a new user workflow.

Type of Change

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

Testing

• I ran bun test — 4,105 passed
• Relevant E2E coverage is not applicable; handler/subprocess regression tests cover the changed handoff, and the published v0 CLI was smoke-tested with deploy --region.
• I ran bun run typecheck
• I ran bun run lint:check
• I ran bun run format:check
• I ran bun run build
• src/assets/ was not modified

Checklist

• I have read the CONTRIBUTING document
• I have added tests that prove the fixes are effective
• Documentation changes are not needed for these internal compatibility corrections
• No new documentation example is needed
• My changes generate no new warnings
• There are no dependent changes that must be published first

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

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.33%. Comparing base (3207575) to head (654d36f).

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2593   +/-   ##
=========================================
  Coverage     96.33%   96.33%           
=========================================
  Files           671      671           
  Lines         51319    51321    +2     
=========================================
+ Hits          49437    49439    +2     
  Misses         1882     1882           

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