Added file-based site verification

My goal is to make the Dictate Button integration as smooth as possible, even for non-developers.

Most vibe-code platforms let you publish your app to a third-level domain, which you can’t verify through DNS, so I’ve added file-based verification for Dictate Button instead.

If you’re vibe-coding with Lovable, Bolt, or v0, adding voice input to your fields is a no-brainer now.