Refactor positionMs and durationMs to be long instead of int

We would save a lot of casting if we switched `positionMs` and `durationMs` to be `long` instead of `int`. Exoplayer uses long and we use int. It might overflow at some point as well which might be why Exoplayer uses long.

No file, test, or entry point is named. Start by locating the declarations and call sites for positionMs and durationMs in the Kotlin Android codebase, then trace the casts and ExoPlayer boundaries. Done means both values use long consistently without the current casts or int overflow risk, with the project’s existing checks still passing.

Written by the indexing model from the issue text.