Add rewrite component for browser image requests

[localnerve]

Because browsers love to request certain images from root, regardless of the markup instructions, add a server rewrite module to handle errant image requests. All others should go to the app router for a 404 via NAVIGATE_FAILURE. Relies on #25 to be fixed.

These asset requests should be rewritten to go to the public asset directory before the static handler.

For example, requests like /mstile-144x144.png should rewrite to the image asset directory, then serve from static.