chore: drop the Matrix delegation

chat.userevolt.app does not resolve any more, so .well-known/matrix was
advertising a homeserver that is gone. _headers existed only to set the
JSON content type on those two files, so it goes with them.

Co-Authored-By: Claude Opus 5 <[email protected]>

.well-known/matrix/client

@@ -1 +0,0 @@
-{"m.homeserver": {"base_url": "https://chat.userevolt.app"}, "org.matrix.msc4143.rtc_foci": [{"type": "livekit", "livekit_service_url": "https://rtc.userevolt.app"}]}

.well-known/matrix/server

@@ -1 +0,0 @@
-{"m.server": "chat.userevolt.app:443"}

README.md

@@ -23,8 +23,6 @@ entire development setup.
 
 ```
 index.html              every piece of copy on the site
-_headers                Cloudflare Pages: JSON content type for the Matrix files
-.well-known/matrix/     Matrix delegation for chat.userevolt.app
 assets/
   css/
     base.css            reset, custom properties, typography

_headers

@@ -1,3 +0,0 @@
-/.well-known/matrix/*
-  Content-Type: application/json
-  Access-Control-Allow-Origin: *