Stability and Performance Improvements for Karoo

Thread Safety

• TestEngine: AtomicInteger, AtomicLong, AtomicReference, Mutex
• AlertManager: Atomic state management
• RampTest: Thread-safe state

Memory Management

• Bounded power samples (MAX=4000)
• History limit (MAX=100)

Karoo SDK

• Connection state tracking
• PlayBeepPattern sound alerts
• UserProfile maxHr for HR zones

Bug Fixes

• Fixed progress calculation for 20-min and 8-min tests
• Fixed HR zones using actual user maxHr
• Fixed O(n) to O(1) in RunningScreen

Build

• R8 minification enabled (17MB → 2.1MB)