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>

src/prometheus/infrastructure/proposer_adapter.py

@@ -29,6 +29,7 @@ class DSPyProposerAdapter(ProposerPort):
         self._proposer = InstructionProposer()
         self._max_retries = max_retries
         self._retry_delay_base = retry_delay_base
+        self.call_count: int = 0
 
     async def propose(
         self,
@@ -56,6 +57,7 @@ class DSPyProposerAdapter(ProposerPort):
                 task_description=task_description,
                 failure_examples=failure_examples,
             )
+        self.call_count += 1
         return Prompt(text=pred.new_instruction)
 
     @staticmethod