> And anyhow I'm obviously a lame-ass hypocrite because I use the 1Pass­word Chrome plu­g­in to fill in forms for me, and this means I type the master password into a browser.

Actually, you don't. When you click the 1Password button in your browser, it sends a request to the 1Password app on your computer via localhost, which then opens a pop-up for you to enter your password. You're entering it in the 1Password app, not in Chrome.