filesystem: HFS+ volume test times out under load (hdiutil exceeds vitest's 5 s default) #5314

Problem

The filesystem test pinned-directory.test.ts > createDirectoryInPlace > creates a directory with a precomposed name on a real HFS+ volume (darwin only) runs hdiutil create, hdiutil attach and hdiutil detach under vitest's default 5000 ms test timeout. On a loaded machine those calls take longer than that. The test then fails with Error: Test timed out in 5000ms, and npm run local:gate exits 1.

On 2026-10-27, while five agents worked in parallel worktrees on one machine, this happened in 3 of about 9 local:gate runs. Each of those runs was for a fetch-only change. Run on its own, the test passes in about 1.5 s.

Reproduce

On macOS under load (several other test suites running), run npm run local:gate, or loop npx vitest run __tests__/pinned-directory.test.ts -t HFS in src/filesystem. The hdiutil steps sometimes go past 5 s.

Expected

The test does not fail on timing alone. It should get an explicit timeout sized for hdiutil (say 30 s, passed as the it timeout argument), not a retry, which AGENTS.md forbids. Alternatively, it should create and attach the image once in a beforeAll with its own timeout.