fix(playground): add debug console logs for event flow

[anonvt]

Summary

• Adds console.debug logs throughout the playground to trace the full event lifecycle
• Helps diagnose why impressions aren't firing on the deployed playground

Debug points

• ensureAnalyticsLoaded(): token presence, script load success/failure, window.TS state after load
• Form submit: element type, card attributes, DOM insertion confirmation
• attachEventListener: which elements get topsort listeners
• topsort CustomEvent: event type and product when received
• Token change handler: when it fires and whether it sets the token
• Clear button: reset confirmation

Notes

• Uses console.debug which only shows with DevTools "Verbose" log level enabled
• No runtime behavior changes

Test plan

• Deploy, open DevTools with Verbose logging, add a product element, check for [Playground] logs

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