Add Landing Dashboard / Home Screen

[Pixie-19]

Description

Currently, OpenDots opens directly into the main workspace with configuration, charts, and AI panels. For new users, this feels overwhelming and unclear because there is no onboarding or starting point.

Expected Behavior

When users first open OpenDots, they should see a simple dashboard / home screen with:

• A short intro to what OpenDots does
• Clear actions like:
  • "Create New Dashboard"
  • "View Docs"

Current Behavior

Users are dropped directly into the full UI with no guidance.

Suggested Solution

• Add a landing/home screen before the main app loads
• Show buttons to:
  • Start a new session
  • Go to documentation