fix: update type hints for async message streaming in GeminiLLM

Author: yarikdevcom

plugins/gemini/vision_agents/plugins/gemini/gemini_llm.py

@@ -1,5 +1,5 @@
 import uuid
-from typing import Optional, List, TYPE_CHECKING, Any, Dict
+from typing import Optional, List, TYPE_CHECKING, Any, Dict, AsyncIterator
 
 from google.genai.client import AsyncClient, Client
 from google.genai import types
@@ -99,7 +99,7 @@ async def send_message(self, *args, **kwargs):
             kwargs["config"] = cfg
 
         # Generate content using the client
-        iterator = await self.chat.send_message_stream(*args, **kwargs)
+        iterator: AsyncIterator[GenerateContentResponse] = self.chat.send_message_stream(*args, **kwargs)  # type: ignore[assignment]
         text_parts : List[str] = []
         final_chunk = None
         pending_calls: List[NormalizedToolCallItem] = []
@@ -149,23 +149,26 @@ async def send_message(self, *args, **kwargs):
                     parts.append(types.Part.from_function_response(name=tc["name"], response=sanitized_res))
 
                 # Send function responses with tools config
-                follow_up_iter = self.chat.send_message_stream(parts, config=cfg_with_tools)  # type: ignore[arg-type]
+                follow_up_iter: AsyncIterator[GenerateContentResponse] = self.chat.send_message_stream(parts, config=cfg_with_tools)  # type: ignore[arg-type,assignment]
 
                 follow_up_text_parts: List[str] = []
                 follow_up_last = None
                 next_calls = []
+                follow_up_idx = 0
 
-                for idx, chk in enumerate(follow_up_iter):
+                async for chk in follow_up_iter:
                     follow_up_last = chk
                     # TODO: unclear if this is correct (item_id and idx)
-                    self._standardize_and_emit_event(chk, follow_up_text_parts, item_id, idx)
+                    self._standardize_and_emit_event(chk, follow_up_text_parts, item_id, follow_up_idx)
 
                     # Check for new function calls
                     try:
                         chunk_calls = self._extract_tool_calls_from_stream_chunk(chk)
                         next_calls.extend(chunk_calls)
                     except Exception:
                         pass
+                    
+                    follow_up_idx += 1
 
                 current_calls = next_calls
                 rounds += 1