feat: add CSV output format support

[swarna1101]

Summary by CodeRabbit

• New Features
  • Added CSV output format support. Users can now export data in CSV format alongside existing table, JSON, and YAML options.

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes add CSV output format support to the application. The cmd/root.go file documents the new "csv" option in the help text, while internal/formatter/formatter.go implements complete CSV formatting logic, including data conversion, nested structure flattening, and CSV writing capabilities.

Changes

Cohort / File(s)	Summary
Documentation Update cmd/root.go	Updates output format flag description to include "csv" as a supported option alongside existing (table, json, yaml).
CSV Support Implementation internal/formatter/formatter.go	Adds FormatCSV constant, formatCSV method, dataToCSVRows converter, and helper utilities (flattenToMap, flattenMap, sortedKeysFromSet, sortedKeys) for CSV serialization. Exposes new IsCSV() public method on Formatter to query current format.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A format most neat, comma-separated rows so sweet,
CSV joins the formatting fleet, now data exports complete!
With flattened maps and ordered keys dancing through the breeze,
The formatter hops with joy, spreading tabular ease! 🎉

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 28.57% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'feat: add CSV output format support' directly and clearly describes the main change in the changeset, which introduces CSV as a new output format option.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feature/csv-output-support

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