Countdown Timer Panel feature

[sakina1303]

Add a new feature to display a basic countdown timer in a WebView panel within VS Code.

Expecting:

• A command in Command Palette: "Open Countdown Timer"
• WebView opens a UI with:

1. Input to set time (in hours/mins/secs)
2. Start, Pause, Reset buttons
3. Live countdown display
4. Alert text and optional simple sound when timer hits zero

[Neha-Sharmaaa]

could u plz assign this issue to me?

[portneon]

please assign this issue to me