Kotlin vibes and a working Android version #pacing

refactored out the Swift code into a layer so it can be ported to Android using Kotlin (actually started using the Tauri plugin system!)

tested the time trial feature with a 5k #pacing

Allow for the final interval to coach you to a specific race time, so you can have earlier intervals help nail a perfect negative split #pacing

allowed a default pace so you can get coaching after you finished the set workout #pacing

automatic workout generation depending on user's history for #pacing - honestly gemini-flash gets most of the way but becomes better to use pro when the user adds more constraints on like total workout distance.