docs: add Session 2 Wallet Integration recording

[danbaruka]

Description

• What problem does this PR solve?
  Session 2 recordings page had no video.
• What is the purpose of this change?
  Embed the Session 2 Wallet Integration recording so it’s available on the site.

Related Issue

N/A

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor (improves code structure or readability without changing functionality)
• Other (please describe):

Changes Made

• Replaced the placeholder in docs/working-group/sessions/q1-2026/10-Wallet-Integration/Session-2/recordings/readme.md with the embedded YouTube video, using the same format as Session 1.

Checklist

• My code follows the project's coding style and guidelines.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation (if applicable).
• My changes generate no new warnings or errors.
• I have added tests that prove my fix is effective or that my feature works.
• I have checked for merge conflicts.
• I have rebased my branch onto the latest main or master branch.