Create dashboard homepage for logged-in users

[livitup]

Description

When a logged-in user visits the home page, they should see a dashboard with relevant stats and quick links to the main objects in the system.

Current Behavior

The homepage is likely a generic landing page that doesn't provide personalized information for authenticated users.

Desired Behavior

Logged-in users should see a dashboard that includes:

Stats/Counts

• Number of codeplugs owned
• Number of zones owned (public vs private)
• Number of channels across all codeplugs
• Number of public zones available to use

Quick Links / Recent Items

• Link to create new codeplug
• Link to create new zone
• List of recent/favorite codeplugs (last 5)
• List of recent/favorite zones (last 5)

Optional Enhancements

• "Getting Started" guide for new users with no codeplugs
• Quick actions (Generate Channels for a codeplug, etc.)
• Activity feed showing recent changes

Acceptance Criteria

• Logged-in users see a personalized dashboard
• Dashboard shows codeplug count with link to codeplugs index
• Dashboard shows zone count with link to zones index
• Dashboard shows quick links to create new codeplug/zone
• Dashboard shows recent codeplugs (clickable)
• Dashboard shows recent zones (clickable)
• Non-logged-in users see the standard landing page
• All tests pass
• No rubocop offenses

Notes

• Consider using cards/widgets for a clean layout
• Should be responsive for mobile users
• Could use Turbo Frames for any dynamic content