feat: add tooltip with Plex token instructions

[phob]

Changes Made

This PR adds a helpful tooltip to the Plex token input field that explains how to obtain a Plex token.

Features

• Added an info icon next to the Plex token field
• Added a tooltip with step-by-step instructions
• Added @radix-ui/react-icons package for the info icon
• Fixed quote escaping in tooltip content

Instructions Added

The tooltip provides clear steps for obtaining a Plex token:

1. Sign in to Plex Web App
2. Click any media item
3. Click the three dots (⋯) and select "Get Info"
4. Click "View XML" in the lower-left corner
5. Find "X-Plex-Token=" in the URL

Technical Details

• Uses shadcn/ui Tooltip component
• Follows NextJS and React best practices
• Maintains consistent styling with the rest of the application

Screenshots

(Please add screenshots during review)