fix: add Watson embedding support to factory

- Add Watson to EmbeddingProvider type definition
- Implement _create_watson_embedding_function in factory.py
- Add Watson to embedding_functions dictionary
- Add comprehensive tests for Watson embedding functionality
- Ensure proper error handling for missing IBM Watson dependencies

Fixes #3582

Co-Authored-By: João <joao@crewai.com>

tests/rag/embeddings/test_factory_enhanced.py

@@ -248,3 +248,68 @@ def test_get_embedding_function_instructor() -> None:
 
         mock_instructor.assert_called_once_with(model_name="hkunlp/instructor-large")
         assert result == mock_instance
+
+
+def test_get_embedding_function_watson() -> None:
+    """Test Watson embedding function."""
+    with patch("crewai.rag.embeddings.factory._create_watson_embedding_function") as mock_watson:
+        mock_instance = MagicMock()
+        mock_watson.return_value = mock_instance
+
+        config = {
+            "provider": "watson",
+            "api_key": "watson-api-key",
+            "api_url": "https://watson-url.com",
+            "project_id": "watson-project-id",
+            "model_name": "ibm/slate-125m-english-rtrvr",
+        }
+
+        result = get_embedding_function(config)
+
+        mock_watson.assert_called_once_with(
+            api_key="watson-api-key",
+            api_url="https://watson-url.com",
+            project_id="watson-project-id",
+            model_name="ibm/slate-125m-english-rtrvr",
+        )
+        assert result == mock_instance
+
+
+def test_get_embedding_function_watson_missing_dependencies() -> None:
+    """Test Watson embedding function with missing dependencies."""
+    with patch("crewai.rag.embeddings.factory._create_watson_embedding_function") as mock_watson:
+        mock_watson.side_effect = ImportError(
+            "IBM Watson dependencies are not installed. Please install them to use Watson embedding."
+        )
+
+        config = {
+            "provider": "watson",
+            "api_key": "watson-api-key",
+            "api_url": "https://watson-url.com",
+            "project_id": "watson-project-id",
+            "model_name": "ibm/slate-125m-english-rtrvr",
+        }
+
+        with pytest.raises(ImportError, match="IBM Watson dependencies are not installed"):
+            get_embedding_function(config)
+
+
+def test_get_embedding_function_watson_with_embedding_options() -> None:
+    """Test Watson embedding function with EmbeddingOptions object."""
+    with patch("crewai.rag.embeddings.factory._create_watson_embedding_function") as mock_watson:
+        mock_instance = MagicMock()
+        mock_watson.return_value = mock_instance
+
+        options = EmbeddingOptions(
+            provider="watson",
+            api_key="watson-key",
+            model_name="ibm/slate-125m-english-rtrvr"
+        )
+
+        result = get_embedding_function(options)
+
+        call_kwargs = mock_watson.call_args.kwargs
+        assert "api_key" in call_kwargs
+        assert call_kwargs["api_key"].get_secret_value() == "watson-key"
+        assert call_kwargs["model_name"] == "ibm/slate-125m-english-rtrvr"
+        assert result == mock_instance