chore: include Pop CLI in the third-party-tools

[AlexD10S]

This PR introduces Pop CLI into the ink! documentation to support quick and easy smart contract development.

What’s included:

• A new section under Third Party Tools → Pop CLI, providing an overview, install instructions, and usage examples.
• A short note added to the Setup page suggesting Pop CLI as an alternative to cargo-contract
  

Pop CLI can improve the developer experience by automating steps like running a Substrate node, offering multiple ink! project templates in the Creating an ink! Project guide, and making contract interaction intuitive in Call Your Contract.

Happy to collaborate further and leave the final call to the ink! alliance.

[Copilot]

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

sidebars.js:107

• The indentation for 'third-party-tools/pop-cli' appears inconsistent with the other entries in the 'Third Party Tools & Libraries' array. Consider aligning its indentation with the other items (e.g., using two additional spaces) for consistency.

      'third-party-tools/pop-cli',

docs/getting-started/setup.md:51

• [nitpick] Consider adding a comma after 'contract interaction' to improve the sentence clarity and flow.

 If you're looking for a more guided, all-in-one developer experience—including project scaffolding with multiple templates, local network setup, and contract interaction you can also try [Pop CLI](../third-party-tools/pop-cli.md)