chore: strip remaining pre-fork version references

Second pass — removes chat-switchboard version numbers from config
field docs, section headers, file headers, and test comments. These
were pre-fork version tags that don't apply to switchboard-core.

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

server/middleware/auth.go

@@ -290,7 +290,7 @@ type TicketValidator interface {
 // WsAuth returns a Gin middleware for the WebSocket endpoint.
 // It authenticates via three methods in priority order:
 //
-//  1. ?ticket=<opaque>  — single-use ticket (preferred, v0.28.8+)
+//  1. ?ticket=<opaque>  — single-use ticket (preferred)
 //  2. ?token=<jwt>      — legacy JWT in query param (deprecated)
 //  3. Authorization header — standard Bearer JWT
 //