feat: add Reset button to counter

[Copilot]

The counter had no way to reset to zero — only increment. Adds a Reset button alongside the existing counter that restores count to 0 and emits a telemetry event.

Changes

src/App.tsx

• New Reset button resets count to 0 on click
• Fires reset_button_clicked telemetry event with previousCount (captured before setCount(0) to avoid stale-closure issues in concurrent React)

<button
  type="button"
  className="counter"
  onClick={() => {
    const previousCount = count
    setCount(0)
    trackEvent('reset_button_clicked', { component: 'App' }, { previousCount })
  }}
>
  Reset
</button>

Tests

• src/__tests__/e2e/app.e2e.spec.ts — asserts Reset button returns counter to Count is 0 and verifies the telemetry event fires with the correct previousCount
• playwright/app.spec.ts — asserts Reset button is visible, clickable, and restores the counter display

Original prompt

Implement the Reset-button issue and print PR description

Created from Copilot CLI via the copilot delegate command.