Add stack to readme

README.md

@@ -1,12 +1,12 @@
 # collabd
 
-editor-agnostic collaborative editing daemon. two vims, one buffer.
+editor-agnostic collaborative editing daemon
 
 ## quick start
 
 ```bash
 bun install
-just dev          # starts daemon on :4040
+just dev # starts daemon on :4040
 ```
 
 in vim (requires 9.0+):
@@ -15,8 +15,13 @@ in vim (requires 9.0+):
 :CollabJoin roomname
 ```
 
-open another vim, join the same room, type in either. magic.
+## stack
+
+- bun runtime
+- yjs for crdt
+- websocket transport
+- vim9script adapter (with bun bridge since vim can't do websocket)
 
 ## more info
 
-see CLAUDE.md for architecture, protocol, and how to add new editor adapters.
+see [CLAUDE.md] for architecture, protocol, and how to add new editor adapters.