fix: tryopenfile updates :input on missing or failing input file

src/files.jl

@@ -104,9 +104,15 @@ function tryopenfile(controller, path; reload::Bool=false)
         turn_load_animation_on(controller)
     end
     #
+    if !isfile(path)
+        @error "Cannot find file" file=path
+        hub[:input][] = nothing
+        return
+    end
     records = loadfile(path)
     if isempty(records)
         @info "Cannot load file" file=path
+        hub[:input][] = nothing
         return
     elseif haskey(hub, :input)
         hub[:input][] = path