feat: app scenes support

[mario-launchdarkly]

Note

Medium Risk
Changes how AppStart traces are classified and timed in multi-scene apps, which affects observability metrics; sample-app credential wiring changed but hardcoded keys were removed from schemes.

Overview
Adds UIScene-aware app start instrumentation: launch timing now pairs sceneWillEnterForeground with sceneDidBecomeActive, classifies cold, warm, and new sceneCreation launches per scene ID, and emits AppStart spans with start.type including sceneCreation. Cold starts measure from process start; additional scenes after the first cold launch are sceneCreation rather than warm.

Introduces shared SceneLaunchClassifier (also used by the MultiScene demo’s launch overlay) and refactors LaunchTracker to delegate classification and subscribe to scene notifications in that order. Span timestamps are derived from system uptime → Date, and LaunchMeter’s launch type enum gains sceneCreation for consistency.

Sample apps (ExampleApp, MultiwindowPad, TestApp) drop Env.swift and Xcode scheme env vars (including embedded mobile keys); config now comes from TestAppShared/Secrets.xcconfig via Info.plist (mobileKey, otlpEndpoint, backendUrl). MultiScene app wires observability startup and a visual launch-stats demo aligned with the new classifier.

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[abelonogov-ld]

Please attach SR and Trace/Logs screenshots, I fetched branch and I couldn't get them work.

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[cursor]

Duplicated enum and dead sceneCreation case in LaunchType

Low Severity

LaunchType and SceneLaunchClassification are duplicated enums with identical cases (cold, warm, sceneCreation) and identical description implementations. This PR adds .sceneCreation to LaunchType, but LaunchMeter (the only consumer of LaunchType) never produces that case — it only ever sets .cold or .warm — making it dead code. LaunchTracker was switched to use SceneLaunchClassification instead, so the extension of LaunchType serves no purpose.

Additional Locations (1)

• Sources/LaunchDarklyObservability/AutoInstrumentation/Launch/SceneLaunchClassifier.swift#L3-L17

 

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