Some tests use manual temp dir cleanup instead of tempfile::TempDir RAII

[karthiknadig]

Summary

Several new tests added in PR #392 use manual temp directory management (std::env::temp_dir() + timestamp + fs::remove_dir_all in cleanup) instead of the RAII tempfile::TempDir pattern.

Affected Files

• crates/pet-pixi/src/lib.rs (line ~112-116)
• crates/pet-windows-registry/src/lib.rs (line ~149-156)
• Other test modules in Improve locator and reporter test coverage #392

Problem

If a test panics before reaching the cleanup code, temp directories are left behind. The RAII approach (already used in crates/pet-uv/src/lib.rs and crates/pet/tests/jsonrpc_server_test.rs) cleans up automatically even on unwind.

Proposed Fix

Replace manual temp dir management with tempfile::TempDir where it isn't already used.

Impact

Minor — leftover temp dirs on CI from panicked tests. Not a correctness issue.