Improve moderator approval dashboard.

[DamSenViet]

Not sure what requirements we want.

[Thulinma]

I think we want:

• To "claim" a batch of patterns as "currently being reviewed by moderator X" in the backend
• Configure how many to load/claim at the same time
• Once the batch is finished, allow easily sending the remainder to "review later" list (sometimes there are patterns that need more context or a second opinion, or are otherwise hard to immediately make a decision on; we want to be able to "skip" those until we finish the easy ones, I think)
• Then, allow reloading (and claiming) a new batch

This workflow ensures that multiple moderators can approve patterns in parallel without all looking at the same patterns, and makes it possible to not get "stuck" with a list of tricky to handle patterns. Should let us quickly onboard a bunch of moderators to help go through the list! 💪

Of course this needs some backend changes too. I'd be happy to get those ready in advance, just tell me what you need operational to work on this and I'll get it set up ASAP. Feel free to propose changes to the API for these steps if you want, or if you're not sure I can propose changes instead and see if you agree it would work to handle everything.