invoke-claude-raises-when-binary-missing

Summary

When the Claude CLI binary isn't installed or isn't in the system's PATH, calling the internal invoke function will crash with an unhandled exception instead of returning a graceful error message. This matters because the ask() function catches most other failure modes, but this one will bubble up as an uncaught exception to whatever code called it, so callers need their own try/except around it or the program will crash.