🎨 Palette: [UX improvement] Context-aware status bar tooltips and state cleanup

[raccioly]

💡 What

• Added explicit, context-aware tooltips for the VS Code extension's status bar item when in an error or unknown state (e.g., "CDD Score: Unknown\nCould not parse score output. Click to see details.").
• Explicitly clears the backgroundColor on the status bar item (statusBarItem.backgroundColor = undefined) during these error states.
• Converted function activate(context) to async function activate(context) to resolve a SyntaxError caused by using await inside a synchronous function.

🎯 Why

When the extension encounters an error reading the CDD score, it gracefully falls back to displaying $(shield) CDD: ?. However, previously:

1. The static tooltip wouldn't explain why the state was unknown.
2. The background color of the status bar item would persist. If the user previously had a failing score (red background) and then triggered an error state, the status bar would show ? but remain red, sending confusing, mixed signals.

📸 Before/After

Before: Status bar shows CDD: ? but might be styled red/yellow from previous runs, and hovering gives generic static text.
After: Status bar shows CDD: ? with the default background color, and hovering explains why the state could not be refreshed.

♿ Accessibility

Improves cognitive accessibility by ensuring developers aren't relying on stale visual cues (lingering red/yellow colors) when the actual state is "unknown." Descriptive tooltips provide clear, readable context for the error rather than requiring users to manually check output logs.

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PR created automatically by Jules for task 3474951075863041236 started by @raccioly

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