Pi: Predictable temporary extension install paths allow local privilege escalation on shared Linux hosts

Pi is a minimal terminal coding harness. From 0.74.0 until 0.78.1, Pi versions with temporary npm or git extension package installs used predictable paths under the operating system temporary directory. On Linux-based multi-user systems, a local attacker who can write to the shared temporary directory could prepare the expected package location before another user runs pi with a temporary extension package source. Pi could then load attacker-controlled extension code in the victim user's process. This vulnerability is fixed in 0.78.1.