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/handlers/notification_test.go

@@ -62,7 +62,7 @@ func setupNotifHarness(t *testing.T) *notifHarness {
 	protected.PUT("/notifications/preferences/:type", notifH.SetPreference)
 	protected.DELETE("/notifications/preferences/:type", notifH.DeletePreference)
 
-	// Admin broadcast route (v0.28.6)
+	// Admin broadcast route
 	admin := api.Group("/admin")
 	admin.Use(middleware.Auth(cfg, stores.Users, userCache))
 	admin.Use(middleware.RequireAdmin(stores))
@@ -560,7 +560,7 @@ func TestNotifications_Unauthenticated(t *testing.T) {
 	}
 }
 
-// ── Admin Broadcast (v0.28.6) ────────────
+// ── Admin Broadcast ────────────
 
 func TestBroadcast_Success(t *testing.T) {
 	h := setupNotifHarness(t)