Relaunch Behavior

Users will keep opening tools from Windows Terminal profiles, IDE tasks, and muscle-memory pwsh/bash sessions. Forcing them to remember "open a nu shell first" is friction. If nu is on PATH, hopping into Nushell for that one command is the polite default:

$ myCLItool status
Nushell is installed, but this shell is not Nushell. Relaunching inside Nushell…
(... tool runs under nu ...)

The tool still requires Nushell as the real host; it does not pretend bash/pwsh are supported runtimes.

Detection and quoting heuristics will harden over time. Early scaffold status — see the repository README for current readiness.