An ATproto social media client -- with an independent Appview.

Fix a bunch of type errors and add a type-check to the github workflows (#837) master

* Add yarn type-check * Rename to yarn typecheck * Fix a collection of type errors * Add typecheck to automated tests * add `dist` to exluded folders tsconfig --------- Co-authored-by: Ansh Nanda <anshnanda10@gmail.com>