Under the hood
A new process can reconstruct which deferred tools an earlier process already surfaced, so they don't need re-announcing.
When starting a new process, the harness can now reconstruct which deferred/lazy-loaded tools a previous process had already surfaced, using deferred_tools_delta attachments, and seeds references to them in the new process so those tools don't need to be re-announced. This is logged as Dynamic tool loading: seeded N tool reference(s).