🎨 Palette: [UX improvement] Enhance README accessibility and clarity

[Igor Holt (igor-holt)]

💡 What: This PR enhances the project's documentation UX by adding a visual architecture diagram, improving badge accessibility, and clearly highlighting the project's experimental status.

🎯 Why: For infrastructure-heavy projects like Arbiter, the README is the primary user interface. These changes make the project's complex architecture more intuitive at a glance and ensure that critical usage warnings are highly visible and accessible.

♿ Accessibility:

• Added title attributes to Markdown badges to provide context for screen readers and mouse-over interactions.
• Used semantic GitHub Alert blocks ([!CAUTION]) for project status, which are well-supported by screen readers and provide high visual contrast.

📸 Visual Changes:

• A new "Architecture" section with a Mermaid diagram representing the flow from Kubernetes to Bare-Metal hardware.
• A yellow/orange caution block at the top of the file warning users about the experimental nature of the project.

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PR created automatically by Jules for task 8358359044523817660 started by Igor Holt (@igor-holt)

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[roomote-v0]

Rooviewer   See task

Reviewed README UX/accessibility updates; no issues flagged.

• No blocking issues found.

_{Mention Roomote (@roomote) in a comment to request specific changes to this pull request or fix all unresolved issues.}

[gemini-code-assist]

Code Review

This pull request updates the README.md to improve accessibility for badges, add a warning regarding the project's experimental status, and include a Mermaid architecture diagram. The reviewer suggested changing the alert type to [!WARNING] for better visual consistency and adding accessibility titles and descriptions to the diagram.

[gemini-code-assist]

The PR description mentions a "yellow/orange caution block", but the [!CAUTION] alert type typically renders in red on GitHub. To achieve the intended yellow/orange color and better align with the "Experimental" status, consider using [!WARNING] instead.

Suggested change

	> [!CAUTION]
	> [!WARNING]

[gemini-code-assist]

To further enhance accessibility as intended in this PR, you can add accTitle and accDescr to the Mermaid diagram. This provides a text alternative for screen readers to describe the diagram's content.

Suggested change

	graph TD
	graph TD
	accTitle: Arbiter Architecture Diagram
	accDescr: Flow diagram showing Arbiter Core bridging Kubernetes with Bare-Metal and GPU resources.