docs: prototype a new landing page

[baszalmstra]

Description

Note

This is not intended to be merged. Its something to show what could be done.

This replaces the current docs homepage with a more focused landing page for Pixi as a cross-platform, language-agnostic package manager for the whole project.

The hero keeps the Material header and footer, but gives the page its own rounded Prefix-inspired visual system. The title, terminal, package constellation, manifest, and tabs all follow the same selected ecosystem. Automatic selection stays silent, pauses while someone interacts with the page, and respects reduced motion and page visibility.

The constellation connects C++, Rust, Node.js, Go, Lua, CUDA, ROS, and PyTorch to one pixi.lock. The corresponding manifest example shows how the project changes per ecosystem. The PyTorch example also demonstrates rich platforms with CPU-only Linux and separate CUDA 12 and CUDA 13 targets.

The ecosystem names stay concrete in the constellation, while the title and manifest tabs use the broader AI, Web, and Robotics labels. The responsive layout keeps the terminal, lockfile, and supported platforms above the desktop fold and collapses cleanly for mobile.

How Has This Been Tested?

• node --check docs/javascripts/landing.js
• mkdocs build --clean
• Playwright validation at 1440, 1366, 1280, 1100, 900, 600, and 390 px
• verified node, tab, title, terminal, manifest, keyboard, automatic-selection, and reduced-motion synchronization
• verified responsive connector endpoints and checked for node overlap and horizontal overflow
• reviewed light, dark, desktop, mobile, and manifest captures

AI Disclosure

• This PR contains AI-generated content.
  • I have tested any AI-generated content in my PR.
  • I take responsibility for any AI-generated content in my PR.

Tools: Codex

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation