fix(tooling): resolve the changeset LEVEL axis package from its manifest, so the 51 nested packages are candidates it can refuse (#16969)

* fix(tooling): resolve the changeset LEVEL axis package by manifest, at any depth

wip

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012GKcPZbMoGq7WPzKLfRBTU

* test(tooling): pin the DEPTH axis with both controls and the new failure mode

wip

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012GKcPZbMoGq7WPzKLfRBTU

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Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]