Implemented a second LLM stage for grammatical review

tests/test_corrections.py

@@ -144,6 +144,33 @@ def test_apply_corrections_replaces_all_repeated_substrings():
     assert result.skipped == []
 
 
+def test_apply_corrections_requires_unique_match_when_configured():
+    transcript = parse_transcript_json(
+        """
+        [
+          {"id": 1, "speaker": "Eric", "start": 0.0, "end": 1.0, "text": "there and there"}
+        ]
+        """
+    )
+    correction = CorrectionCandidate(
+        id=1,
+        original_text="there",
+        corrected_text="their",
+        confidence=0.8,
+    )
+
+    result = apply_corrections(
+        transcript,
+        [correction],
+        confidence_threshold=0.8,
+        replacement_mode="require_unique",
+    )
+
+    assert result.transcript[0].text == "there and there"
+    assert len(result.skipped) == 1
+    assert "more than once" in result.skipped[0].reason
+
+
 def test_apply_corrections_skips_empty_original_text():
     transcript = _transcript()
     correction = CorrectionCandidate(
@@ -163,3 +190,8 @@ def test_apply_corrections_skips_empty_original_text():
 def test_apply_corrections_rejects_invalid_threshold():
     with pytest.raises(AuditaValidationError):
         apply_corrections(_transcript(), [], confidence_threshold=1.1)
+
+
+def test_apply_corrections_rejects_invalid_replacement_mode():
+    with pytest.raises(AuditaValidationError):
+        apply_corrections(_transcript(), [], confidence_threshold=0.8, replacement_mode="unknown")