feat: v0.2.0 sprint — ground truth eval, crossover/mutation, checkpointing, similarity guards, dataset loader, CLI commands, extended test coverage

Aggregates all v0.2.0 sprint work (GARAA-30 through GARAA-40) and fixes
2 integration tests that broke when the codebase went async (DSPyLLMAdapter
and full pipeline tests now properly await coroutines).

277 tests pass (260 unit + 17 integration).

Co-Authored-By: Paperclip <noreply@paperclip.ing>

tests/unit/test_error_handling.py

@@ -278,6 +278,7 @@ class TestPerCallIsolation:
         adapter._judge_dimensions = []
         adapter._dimension_names = ""
         adapter._weights = {}
+        adapter.call_count = 0
 
         # Mock _judge to fail on first call, succeed on second
         call_count = 0