GET-056b: apply the GET-056 ruling to every kind-keyed gate, incl. sub checkout

Now
DONE

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Context

GET-056 fixed the flat D5 gate (be/verbs/get/get.js:1054 now f||x + 3-side isBinary) but the SUB checkout path has its own twin gate at be/shared/checkout.js:203 still reading kind === "f" its comment codifies the overturned "symlink/exec clean-reset". This unfixed twin clobbered the five exec-bit files in the GET-057 incident.

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WIP

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