Perhaps you could share details of how your environment is secured, more to the point what can you do?
Can you download files, what browsers do you have or can you install a browser, is your internet restricted, does it restrict known sites, or unknown sites, have you used tiddlyspot or looked at Marffapad to host your wiki, have you looked at notself even just in browser session saving, can you send and recieve email attachments, have you or do you know someone who can host a tidlywiki for you, does your organisation use google or microsoft cloud platforms. Can you use a thumb drive or dvd to place files on your computer.
Some email system block some file types as attachments to stop hackers, but you can treat them differently to intentionaly get them transfered with manual intervention. What email system do you use?
A tiddlywiki can be treated as a document rather than software in many cases.
Regards
Tony