fix(docs): replace YouTube channel link with actual playlist in Quickstart

[alelpoan]

What does this PR do?

The "Hermes Agent Tutorials & Use Cases" link in the Quickstart page points
to the YouTube channel page instead of the actual playlist. Users clicking
"see the full playlist" land on the channel homepage, not the playlist.

Related Issue

Fixes #

Type of Change

• 📝 Documentation update

Changes Made

• website/docs/getting-started/quickstart.md — replaced YouTube channel URL
  with direct playlist URL

How to Test

1. Open https://hermes-agent.nousresearch.com/docs/getting-started/quickstart
2. Click "Hermes Agent Tutorials & Use Cases" link
3. Confirm it now opens the playlist directly

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix
• I've run pytest tests/ -q — N/A
• I've added tests — N/A
• I've tested on my platform: Windows 11

Documentation & Housekeeping

• I've updated relevant documentation — N/A
• I've updated cli-config.yaml.example — N/A
• I've updated CONTRIBUTING.md — N/A
• I've considered cross-platform impact — N/A
• I've updated tool descriptions/schemas — N/A

Screenshots / Logs

Before: clicking the link opens YouTube channel homepage

After: clicking the link opens the actual playlist