Cheapskate question.

[SeaSharp2]

I am trying to delay purchasing a commercial Ext licence for a few months but I have an immediate need to test my Ext application on a remote web server that is connected to the public internet.

My development PC will be the only test browser client and I will doctor my application

[devnull]

I am not sure why you are so worried about the "deadly embrace" of the GPL. seems theres some education that needs to be done on that front yet...
When and how you "release" your application is entirely up to you. From my point of view, I see what you describe as still personal use, even if all the Ext files are hosted on your webserver too. Of course since it is javascript, all the source is there for anyone that happens to stumble upon it anyway.
But having said that, someone finding your code does not constitute a release and would not bind you to any sort of license or contract.