Cold Android launches can be classified as warm #6363

On Android API 31/33, the critical Maestro App Start Tests flow has repeatedly failed its App Start Type: COLD assertion. The failures may indicate that genuinely cold launches are being reported as warm, rather than only a UI-test timing issue.

• In AppStartMetrics, the pre-API-35 fallback uses firstIdle when determining app-start type; an idle main looper before the first activity can classify the start as warm.
• The CI flow launches a fresh app and checks for COLD in appStart.yaml. Existing logs confirm the assertion fails, but do not establish whether the displayed value was WARM or blank; the production impact is therefore still unconfirmed.
• Reported by Nelson Osacky.

Action taken on behalf of Nelson Osacky.