Summary

Fixes the aggregate tool-shell.test.ts hang by keeping each test's registry use inside one borrowed Location layer and invalidating that Location when the test body exits.

The production Location cache intentionally retains services for 60 minutes. The test previously let every temporary Location retain its full watcher/process service graph, eventually stalling acquisition of another Location layer. Effect.ensuring now releases the test Location on success, failure, or interruption.

Verification

• Reproduced on clean v2: the full file stalled after several individually passing cases
• bun test --timeout 5000 test/tool-shell.test.ts passed three consecutive aggregate runs (39/39 cases)
• bun typecheck in packages/core
• Full-repo pre-push typecheck passed
• Prettier and file-scoped oxlint: 0 errors (existing warnings only)