🎨 Palette: Improve Welcome screen command visibility

[AhmmedSamier]

💡 What: Moved the slash command trigger (e.g., /all) from the label to the description field for Welcome items in the QuickPick UI. The explanation and keyboard shortcut remain in the detail field.
🎯 Why: To improve the visibility and scanability of the primary interaction trigger. Putting it in the description field uses VS Code's native visual hierarchy (right-aligned, muted color) to separate the friendly name from the technical command, reducing cognitive load.
📸 Before/After: N/A
♿ Accessibility: Improves clarity for screen reader users by separating the name and the command.

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PR created automatically by Jules for task 1950424283835398538 started by @AhmmedSamier

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