[native] introduce AutoJoinCommunityHandler
Summary:
AutoJoinCommunityHandler handles the logic for getting the user to automatically join communites that are tagged to farcaster channels that the user follows.
In a subsequent diff we will update this logic so we background these communites/threads by default
Linear task: https://linear.app/comm/issue/ENG-7959/query-the-users-channels-that-they-follow-on-app-start + https://linear.app/comm/issue/ENG-7960/download-all-the-relevant-blobs-based-on-the-viewers-farcaster
Depends on D12064
Test Plan:
- Created a new community called Run club
- Tagged /sovereignty farcaster channel to Run club
- Logged out of my account
- Created a new account with my fid hardcoded with my fid hardcoded in useCurrentUserFID
- Confirmed that the new user auto joined run club since /sovereignty is a farcaster channel that my fid follows
Confirmed that when the authorization header is present, we were able to fetch the blobs, and when the authorization header were not present, the fetch calls failed
Reviewers: kamil, ashoat, bartek
Reviewed By: ashoat, bartek
Subscribers: bartek, ashoat, tomek
Differential Revision: https://phab.comm.dev/D12065