Stack Trace Decoder

A stack trace is an array of frames, index 0 = top (where it threw). Write firstOwnFrame(frames) — frames are objects { fn, file }; return the first frame whose file starts with "app/" (your code), skipping framework frames; return null if none. Write errorKind(message) mapping: contains "is not a function" => "type", contains "Cannot read prop" => "shape", otherwise "other".

Difficulty: intermediate