Janis
288a1c5ac3
Test-driven fixes for code review blockers NCS-16: **Observable (CRITICAL):** Added synchronized blocks to subscribe, unsubscribe, notifyObservers, and observerCount to prevent race conditions when concurrent threads register observers while notifications are dispatched. **CommandInvoker (IMPORTANT):** Added synchronized blocks to all methods (execute, undo, redo, history, getCurrentIndex, canUndo, canRedo, clear) to ensure atomic access to mutable state (executedCommands, currentIndex). Tests: - Added ObservableThreadSafetyTest: 3 tests for concurrent subscribe/unsubscribe/notify - Added CommandInvokerThreadSafetyTest: 2 tests for concurrent execute/undo/redo - All 54 existing tests remain green - Full build passes with 100% core coverage Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>