-e/--explain generates the command, asks the LLM to summarize it, prints the
explanation, and then asks for confirmation before execution. No command runs
until you approve.

Example shape:
Generated command:
  find . -name '*.py'

Explanation:
  Searches for Python files under the current directory.

Use explain mode when learning a new toolset, when using --unsafe, or whenever
you want to sanity-check the intent before running anything.
