Fixed 2 remaining test failures:
1. NODE_DB_PATH environment variable test:
- Issue: Null byte handling error in shell command
- Fix: Use existing getProcessEnv helper function that properly escapes null bytes
- This helper was already designed for reading /proc/*/environ files
2. User switching test:
- Issue: Test checked PID 1 (su process) instead of actual node process
- Fix: Find and check the node process owner, not the su wrapper
- When using --user root, entrypoint uses 'su' to switch to nodejs user
- The su process (PID 1) runs as root but spawns node as nodejs
Also increased timeouts to 3s for better CI stability.