The redesigned action hook marked every accepted install command as Checking
Peers. That is correct while the launcher is asking peers for file details, but
it is wrong for a game that is already downloaded and only needs local archive
installation.
Track the already-downloaded path separately and optimistically show Installing
until the backend install lifecycle event arrives. Peer-backed downloads keep the
existing Checking Peers state.
Test Plan:
- git diff --check
Refs: user redesign nitpick about install button state
ddidderr
74d9266723
