Add text episode type (#46)

Add a new `text` episode type and update the `extract_nodes` function to handle it.

* **EpisodeType Enum:**
  - Add `text` to the `EpisodeType` enum in `graphiti_core/nodes.py`.
  - Update the `from_str` method to handle the `text` episode type.

* **extract_nodes Function:**
  - Update the `extract_nodes` function in `graphiti_core/utils/maintenance/node_operations.py` to handle the `text` episode type.
  - Use the `message` type prompt for both `message` and `text` episodes.

---

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graphiti_core/nodes.py

@@ -46,10 +46,13 @@ class EpisodeType(Enum):
         or "assistant: I'm doing well, thank you for asking."
     json : str
         Represents an episode containing a JSON string object with structured data.
+    text : str
+        Represents a plain text episode.
     """
 
     message = 'message'
     json = 'json'
+    text = 'text'
 
     @staticmethod
     def from_str(episode_type: str):
@@ -57,6 +60,8 @@ class EpisodeType(Enum):
             return EpisodeType.message
         if episode_type == 'json':
             return EpisodeType.json
+        if episode_type == 'text':
+            return EpisodeType.text
         logger.error(f'Episode type: {episode_type} not implemented')
         raise NotImplementedError
 

graphiti_core/utils/maintenance/node_operations.py

@@ -72,7 +72,7 @@ async def extract_nodes(
 ) -> list[EntityNode]:
     start = time()
     extracted_node_data: list[dict[str, Any]] = []
-    if episode.source == EpisodeType.message:
+    if episode.source in [EpisodeType.message, EpisodeType.text]:
         extracted_node_data = await extract_message_nodes(llm_client, episode, previous_episodes)
     elif episode.source == EpisodeType.json:
         extracted_node_data = await extract_json_nodes(llm_client, episode)