[Refactor] Simplify parseCommand control flow using guard clauses

[gonzaloriestra]

WHY are these changes introduced?

Refactor control flow in parseCommand to improve code readability and maintainability without altering observable behavior.

WHAT is this pull request doing?

Refactored parseCommand in packages/cli-kit/src/public/node/system.ts to flatten the main loop logic by replacing nested if/else conditionals with an early continue guard clause for inQuote character processing.

How to test your changes?

CI

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

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PR created automatically by Jules for task 2392441914162961499 started by @gonzaloriestra

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