Fix input syntax in CLI help example

[brbousnguar]

What Problem This Solves

The input example shown by dw --help and reproduced in the README uses a space between the input name and path. Picocli parses the -i option as a map, so its required syntax is name=path; copying the existing example results in a command that does not run.

Why This Change Was Made

• Correct the help footer to use -i payload=<fullPathToUser.json>.
• Keep the README's captured help output consistent with the CLI.
• Add a focused test that executes the CLI with the documented name=path input form.

User Impact

Users can copy the input-file example from dw --help or the README and run it successfully.

Evidence

• ./gradlew native-cli:test
• 16 tests passed with zero failures (15 DataWeaveCLITest tests and 1 DependencyManagerTest)
• git diff --check

Fixes #113

[mlischetti]

LGTM

[mlischetti]

@brbousnguar thanks for your contribution! In order to proceed with the merge, the commits must have verified signatures. Can you please verify it. Thanks!