feat(docs): add accent scale color override support (accent-1 through accent-12)

[sbawabe]

Description

Refs: Part 1 of 2 for accent scale color customization feature

Adds support for users to override individual accent scale colors (accent-1 through accent-12) in the docs.yml configuration. This allows fine-grained control over the Radix color scale instead of only being able to set the base accent-primary color.

Requested by: @sbawabe
Link to Devin run: https://app.devin.ai/sessions/38d27293b51e4014b58438ae485fbd31

Changes Made

• Added 12 new optional properties (accent-1 through accent-12) to ColorsConfiguration in the docs.yml schema
• Each property supports the existing ColorConfig type (string or light/dark themed config)
• Regenerated the TypeScript SDK to include the new properties with serialization support
• Added documentation for each accent scale step describing its typical usage

Example usage in docs.yml:

colors:
  accent-primary: "#818CF8"
  accent-1:
    light: "#f5f3ff"
    dark: "#1a1625"
  accent-9:
    light: "#6366f1"
    dark: "#818cf8"

Testing

• Lint checks passed (pnpm lint:biome)
• Unit tests added/updated (schema-only change, no logic to test)
• Manual testing completed

Review Checklist

• Verify property naming matches expected fern-platform implementation
• Confirm documentation accurately describes Radix color scale steps
• Note: A companion PR in fern-platform is required to utilize these overrides

[devin-ai-integration]

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