Use WorkerLocation for location in workers

Editor assessment

The subject states the correction exactly: WorkerLocation is used for the location inside workers. Type fix and the op_crates/web scope are accurate, both web platform concepts are named, and spec-conformance readers immediately understand the alignment. No body, acceptable since the corrected mapping is fully described. No footers beyond the PR number. Hygiene is clean. A precise, complete message for a web-compatibility fix in the worker environment.