Clearer message when a timeout command can't be checked

Before running a shell command, Claude Code tries to work out what it will do. When a timeout command has an option or value that cannot be checked in advance, the explanation now reads as a plain sentence instead of a terse technical one.

Separately, the check for a -c-style option, which tells a program to run a command given as text, now looks at the command's separated arguments instead of matching a pattern against the raw text.