[omartelo]

Summary

• The state menu on the Pulls screen gets Approved, between Open and Closed: the open pull requests whose reviewDecision is APPROVED.
• It narrows the Open read in pullsStore.list, so there is no extra gh call and no backend or RPC change. The quick filters, their counts and the detail's previous and next all read the narrowed list.
• It sees the same 50 most recently updated open pull requests the Open list asks for.

Test plan

• TestPullsStoreApprovedNarrowsTheOpenRead: only approved rows, the Open read left whole, one gh read shared by both states
• Local gate green on the backend and on native/