ReferenceError 'can't access lexical declaration musicMode before
initialization' halted the page script at line 692 (the localStorage
restore), which left every event handler unbound — including 'enter',
so users couldn't join a room at all.
Cause: the persistence patch placed the restore right after the handle
restore, but the let-declarations for those vars still lived 400+ lines
further down. `let` puts the binding in the temporal dead zone until
its declaration executes — reads from above throw.
Fix: declare `let musicMode, micDeviceId, cameraDeviceId` at the top
near the other prefs, drop them from the later `let` lines so the page
init doesn't re-shadow them.
Russell Ballestrini
3539171fd3