docs: define CPA blue/green brand and refresh package hero

[ulises-jeremias]

Description

Mark Create Python App as public Beta across org profiles and sibling websites, and align CPA website visuals with the org blue→green node-graph brand.

Type of Change

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Spot-check brand tokens / logos / ecosystem badges
• pnpm test / pnpm type-check where applicable

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

Made with Cursor

[ulises-jeremias]

@coderabbitai review