🎨 Palette: Improve status bar state transitions

[raccioly]

💡 What

Updated the VS Code extension to explicitly reset the status bar background color to undefined when the CDD score check fails or enters an unknown state. Also added descriptive tooltips to explicitly indicate 'Unknown' or 'Error' states, and fixed a syntax error by converting the activate function to async.

🎯 Why

In the VS Code API, custom background colors (like warningBackground) persist across state updates unless explicitly reset. If an error occurs, a previous warning state's color could linger, providing confusing and inaccurate visual feedback to the developer. The added tooltips ensure developers have context for the status bar icon.

📸 Before/After

• Before: If the CLI threw an error after previously scoring < 60, the status bar would display the fallback icon ($(shield) CDD: ?) but remain colored warning yellow/red, with no explanation in the tooltip.
• After: The status bar clears the warning background and provides a tooltip reading "CDD Score: Error\nClick to see details" or "CDD Score: Unknown", making the current state immediately clear.

♿ Accessibility

Improves accessibility by ensuring visual color cues accurately match the system's underlying state, and by providing explicit text via tooltips for users who may rely on screen readers or hover interactions rather than color alone to deduce status.

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PR created automatically by Jules for task 4385439644776734721 started by @raccioly

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