Root cause: tinypool worker teardown calls kill() which returns EPERM
in the act_runner host environment on Node.js v25.2.1. Tests pass but
the vitest process crashes during cleanup, causing CI failure.
Fix: --pool forks CLI flag on every package/service test script, plus
pool: 'forks' in all vitest.config.ts files. This uses child_process.fork()
worker management which handles termination cleanly.
60 package.json files updated, 10 vitest.config.ts files updated.
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