fix(server): restore PR detection without HOME - #4985

💭 I'm reviewing the os-jank.ts file. This is a pure helper module without Effect service dependencies, and the test file properly adds focused tests for the new hydratePosixHome behavior. The imports follow conventions correctly, and the pure function with callback strategy default is an intentional design choice that doesn't violate any patterns. The test appears to be checking that HOME hydration works independently of process environment variables. Since there are no findings, I need to respond with success in JSON format per the schema — the check defaults to failure, but with no violations found, the state should be success with "All clear" as the title.