Remove dead Go types and event code

- Delete unused Grant struct (persona-era, zero references)
- Delete CompositeModelKey (never called)
- Remove dead comment-only type stubs (NoteGraph, ProjectChannel, etc.)
- Remove empty Chat/Channel event sections from route table
- Remove dead chat.typing/channel.typing condition in WS subscriber
- Update bus doc examples and test labels to use real event names

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/events/ws.go

@@ -250,13 +250,6 @@ func (c *Conn) subscribeToBus() {
 			return
 		}
 
-		// Don't echo typing events back to the sender
-		if strings.HasPrefix(e.Label, "chat.typing.") || strings.HasPrefix(e.Label, "channel.typing.") {
-			if e.SenderID == c.userID && e.ConnID == c.id {
-				return
-			}
-		}
-
 		// Room filtering: if event has a room, only send if conn is in that room
 		if e.Room != "" && !c.rooms[e.Room] {
 			return