refactor: singleton `octokit` instance for shared throttling state

[gr2m]

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[travi]

are we wanting to include this refactor in the ESM change, or follow up with it afterward? i've had no problems in my testing with the current beta that includes the ESM change for our two candidate plugins, so wondering if we promote those candidates or wait for this change to go in

[gr2m]

only comments are calling out most of your todos. am i correct to assume that is most of what remains for this to still be draft

correct

are we wanting to include this refactor in the ESM change, or follow up with it afterward

I planned to give this another go today but I won't have time. I'd say let's go ahead with the ESM change and then do this afterwards.