Ely Office: six offline-first desktop apps in Rust and GPUI

ElyDoc, ElyTable, ElyShow (LibreOfficeKit), ElyPDF (MuPDF), ElyTree (Git),
ElyMark (Milkdown and CodeMirror in CEF). ElyMail and ElyAgent follow.

tests/fixtures/web-outside/evil.js

@@ -0,0 +1,2 @@
+// Outside the content folder; it must never run.
+window.outsideRan = true;