feat: O11Y-601 - Add Android launch time instrumentation

[agrognetti]

Summary

This commit introduces automatic instrumentation for Android application launch times. It measures and reports two key metrics:

• Time to Initial Display (TTID)
• Time to Full Display (TTFD)

The instrumentation classifies launches as cold, warm, or hot and records the durations as histogram metrics (app.launch.duration.ttid and app.launch.duration.ttfd). These metrics include attributes for the launch type and the specific activity being launched.

The implementation also includes:

• Adding the dependency androidx.activity:activity.
• Updating the Android compile SDK version to 36 (Required for the dependency added)

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Note

Adds Android launch-time metrics (TTID, TTFD), integrates instrumentation into the SDK, switches metrics export to delta temporality, and updates compileSdk to 36 with new metric APIs and demo triggers.

• SDK:
  • Launch time instrumentation: Add LaunchTimeInstrumentation to record app.launch.duration.ttid and app.launch.duration.ttfd with launch.type and launch.activity attributes.
  • Integration: Wire instrumentation into InstrumentationManager (enabled when metrics are on).
  • Metrics export: Use delta temporality via AggregationTemporalitySelector.deltaPreferred() for OTLP and debug exporters; adjust periodic reader interval to milliseconds.
  • Dependencies/Config: Add androidx.activity:activity; bump compileSdk to 36.
• E2E demo app:
  • Add UI buttons to trigger new metric types; update ViewModel with recordHistogram, recordCount, recordIncr, recordUpDownCounter and rename gauge metric to test-gauge.
  • Bump compileSdk to 36.

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[tanderson-ld]

No specific changes requested. Consider adding tests where possible.

I just have a general feeling that there may be a problematic state that can arise from an unexpected ordering of callbacks / race condition, but if every callback is known to come on one thread (the main thread), then unit tests should be enough to cover it.