chore: refactor workspaces query to use window function (#5079)

* Use window function in query

* Convert workspace rows and unpack count

* Update types

* Fix Scan bug

* Remove getCountError

coderd/autobuild/executor/lifecycle_executor.go

@@ -99,13 +99,14 @@ func (e *Executor) runOnce(t time.Time) Stats {
 	// NOTE: If a workspace build is created with a given TTL and then the user either
 	//       changes or unsets the TTL, the deadline for the workspace build will not
 	//       have changed. This behavior is as expected per #2229.
-	workspaces, err := e.db.GetWorkspaces(e.ctx, database.GetWorkspacesParams{
+	workspaceRows, err := e.db.GetWorkspaces(e.ctx, database.GetWorkspacesParams{
 		Deleted: false,
 	})
 	if err != nil {
 		e.log.Error(e.ctx, "get workspaces for autostart or autostop", slog.Error(err))
 		return stats
 	}
+	workspaces := database.ConvertWorkspaceRows(workspaceRows)
 
 	var eligibleWorkspaceIDs []uuid.UUID
 	for _, ws := range workspaces {