feat: add agent pages and agent playground

[ferruhcihan]

📌 Summary

This PR adds agent pages and Agent Playground.

Ticket: https://track.akamai.com/jira/browse/APL-1142

🔍 Reviewer Notes

Testing:

Please check the testing document.

Considerations

• I have tested the changes in both light and dark mode.
• I have considered the need for new unit tests.
• I have tested the changes on a cluster.
• I have included relevant documentation updates.
• I have an approved Figma design or have reflected my changes in Figma
• I have verified that the UI/UX is consistent in major browsers (e.g., Chrome, Firefox, Safari, Edge).
• I have tested the changes for responsiveness in different screen resolutions.
• I have tested expected error states and verified that the user is presented with informative error messages.
• I have tested the feature with unusual or extreme inputs (e.g., very long strings, empty states, clicking a button multiple times quickly).