Update docs and action with new flags

[flaticols]

Summary

• Add missing action inputs (include-unexported, include-internal, ignore, output)
• Add action outputs documentation
• Add exit codes section to README
• Expand standalone usage examples
• Add jsontest to CLAUDE.md test structure

[Copilot]

Pull request overview

This PR enhances the positionless GitHub Action and documentation by adding support for four new configuration flags that control analyzer behavior and output formatting.

Changes:

• Added four new action inputs: include-unexported, include-internal, ignore, and output with proper implementation in the action's shell script
• Enhanced README with expanded standalone usage examples, action outputs documentation, and a new exit codes reference section
• Updated CLAUDE.md to document the jsontest directory in the test structure

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
action.yml	Adds four new input parameters and implements their corresponding CLI flags in the analyze step
README.md	Updates documentation with new usage examples, action inputs/outputs tables, exit codes section, and enhanced flag descriptions
CLAUDE.md	Adds jsontest to the documented test directory structure

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