extdeps versioning program closeout

[gunbai-bot]

Auto-opened by session-dashboard for session still-ant-248.
Pushing to session/still-ant-248 advances this PR.

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[gunbai-bot]

Closing — superseded wrong abstraction (RestApiPathVersion/UpstreamSpecCitation fidelity carriers). Same rejection as #5314/#5301/#5310. Approved versioning program is #5311 base + ecosystem slices (#5309/#5307/#5315/#5308) + #5322 constraints. still-ant-248 closeout session archived; not a recoverable branch.