add: java queue .peek() method term entry

[Mohit5Upadhyay]

Description

This PR adds a new term entry for the content/java/concepts/queue/terms/peek/peek.md method in Java.

• Adds a clear explanation of .peek() usage
• Includes multiple real-world examples
• Demonstrates handling of empty queues safely
• Adds a Frequently Asked Questions (FAQ)

Issue Solved

Closes #7367

Type of Change

• Adding a new entry

Checklist

• [✅] All writings are my own.
• [✅] My entry follows the Codecademy Docs style guide.
• [✅] My changes generate no new warnings.
• [✅] I have performed a self-review of my own writing and code.
• [✅] I have checked my entry and corrected any misspellings.
• [✅] I have made corresponding changes to the documentation if needed.
• [✅] I have confirmed my changes are not being pushed from my forked main branch.
• [✅] I have confirmed that I'm pushing from a new branch named after the changes I'm making.
• [✅] I have linked any issues that are relevant to this PR in the Issues Solved section.

[Mohit5Upadhyay]

Hi @mamtawardhani 👋

I've submitted a PR for the Issue to add .peek() method term entry under Java Queue.

Please take a moment to review it when convenient.
Let me know if any adjustments or suggestions come up—I'd be happy to make improvements.

Thanks in advance for your time!

[mamtawardhani]

Looks good for a second round of review. 🚀