Function launcher_for_effective_env 

pub fn launcher_for_effective_env(
    env: &[(OsString, OsString)],
    cwd: Option<&Path>,
    kind: ScopeKind,
) -> Option<ScopeLauncher>

Fresh, bounded availability check. Synchronous callers (PTY and detached daemon spawn) may wait up to three seconds. Async callers must offload it. Probe failure selects direct launch. After success, wrapper failure is an error, NEVER a reason to replay the command: availability can race, and the wrapped command may already have executed. This is not a launch handshake. kind picks the slice key (tool_scope_slice / daemon_scope_slice), read from the config this call loads.