feedback when importing DOT fails

[brandly]

looks like the error is swept under the rug with Result.withDefault GF.default

kite/src/Main.elm

Lines 672 to 675 in a5c8fd6

	fileContent
	|> DotLang.fromString
	|> Result.map GraphFile.DotLang.Decode.fromDot
	|> Result.withDefault GF.default

any ideas how to display this feedback? i mention this problem and proposed a "toast" system, which we'd have to build out. maybe that's worth doing. maybe there's something else we should do.