fix(cli): port-forward: update workspace last_used_at (#12659)

This PR updates the coder port-forward command to periodically inform coderd that the workspace is being used:

- Adds workspaceusage.Tracker which periodically batch-updates workspace LastUsedAt
- Adds coderd endpoint to signal workspace usage
- Updates coder port-forward to periodically hit this endpoint
- Modifies BatchUpdateWorkspacesLastUsedAt to avoid overwriting with stale data

Co-authored-by: Danny Kopping <danny@coder.com>

coderd/database/dbmem/dbmem.go

@@ -1046,6 +1046,10 @@ func (q *FakeQuerier) BatchUpdateWorkspaceLastUsedAt(_ context.Context, arg data
 		if _, found := m[q.workspaces[i].ID]; !found {
 			continue
 		}
+		// WHERE last_used_at < @last_used_at
+		if !q.workspaces[i].LastUsedAt.Before(arg.LastUsedAt) {
+			continue
+		}
 		q.workspaces[i].LastUsedAt = arg.LastUsedAt
 		n++
 	}