[Woo POS] [Design System] Create a color palette for POS and corresponding SwiftUI colors

[jaclync]

Part of #15061

Description

This pull request introduces a new color palette for POS based on the Design System table 1qcjzXitBHU7xPnpCOWnNM-fi-19_19221 / color roles 1qcjzXitBHU7xPnpCOWnNM-fi-437_20681. The changes include the addition of new color definitions in Swift and corresponding color assets as an Xcode color asset catalog. The new colors are not used in the code yet, they will replace existing POS colors in future PRs to keep reasonably sized PRs.

I decided to go with a color palette instead of all code, for easier visualization of both light and dark mode colors and because these colors are not meant to be dynamic (at least for now). We can easily compare the colors with the design system and update them in the future.

New color definitions:

• WooCommerce/Classes/POS/Colors/Color+POSColorPalette.swift: Added an extension to the Color class defining various POS-specific colors such as primary, secondary, surface, and status colors.

New color assets:

• WooCommerce/Classes/POS/Colors/POSColorPalette.xcassets: Added the main contents file for the color assets. There are 31 colors from the design system table.

Steps to reproduce

I'd recommend testing the PR by reviewing the POSColorPalette color catalog, where most of the diffs are from. You can compare each color with the corresponding one in 1qcjzXitBHU7xPnpCOWnNM-fi-19_19221 / color roles 1qcjzXitBHU7xPnpCOWnNM-fi-437_20681 (the names in the catalog are lowerCamelCase but I'm open to changing it if it helps with readability). I also named the colors with a pos prefix to avoid potential conflicts with future color palettes.

Testing information

If you'd like to try any of the new colors, feel free to try returning .posTextPrimary for posPrimaryText color for example.

Screenshots

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• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

Reviewer (or Author, in the case of optional code reviews):

Please make sure these conditions are met before approving the PR, or request changes if the PR needs improvement:

• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
• Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• Manual Testing: The author listed all the tests they ran, including smoke tests when needed (e.g., for refactorings). The reviewer confirmed that the PR works as expected on all devices (phone/tablet) and no regressions are added.

[dangermattic]

	1 Warning
⚠️	This PR is larger than 300 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr15063-877d6b1
	Version	21.6
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	877d6b1
	App Center Build	WooCommerce - Prototype Builds #12818

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[iamgabrielma]

LGTM! 🚢

[iamgabrielma]

Great change! Much much easier to work with colors with the palette rather than code-only.