Fix performance of feed reordering and add layout animations

[pfrazee]

Changes the "Edit Feeds" screen to bundle all of the changes into one save action. Also adds animations. Tested on web, ios sim, and android sim.

Mobile	Desktop
https://github.com/user-attachments/assets/9c8f6fe6-da36-47f0-871c-70f4d42a8be7	https://github.com/user-attachments/assets/19258a16-e5e6-438a-abfc-c8984a3b5370

[github-actions]

Old size	New size	Diff
7.89 MB	7.89 MB	1.28 KB (0.02%)

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[haileyok]

lgtm, works on both ios and web. also checked reduced motion. could maybe play w/ animation duration (150?)

[estrattonbailey]

Niiiiice. Long overdue.

New brain worm to fix one day: the non-centered ViewHeader title when there's a button in there lol.

Also one small thing, I feel like the save button may get missed. Unsure on options. Maybe instead of the button in the header we add a section below the header so we can add text like "When you're done press save" or something.

[pfrazee]

@estrattonbailey agree, we should add a todo to replace that header