Support constraining Gemini model output to specified response schema

If the response_schema argument is passed to
send_message_to_model_wrapper it is used to constrain output by Gemini
models

src/khoj/processor/conversation/google/gemini_chat.py

@@ -121,6 +121,7 @@ def gemini_send_message_to_model(
     api_key,
     model,
     response_type="text",
+    response_schema=None,
     temperature=0.6,
     model_kwargs=None,
     tracer={},
@@ -135,6 +136,7 @@ def gemini_send_message_to_model(
     # This caused unwanted behavior and terminates response early for gemini 1.5 series. Monitor for flakiness with 2.0 series.
     if response_type == "json_object" and model in ["gemini-2.0-flash"]:
         model_kwargs["response_mime_type"] = "application/json"
+        model_kwargs["response_schema"] = response_schema
 
     # Get Response from Gemini
     return gemini_completion_with_backoff(

src/khoj/processor/conversation/google/utils.py

@@ -66,6 +66,7 @@ def gemini_completion_with_backoff(
         max_output_tokens=MAX_OUTPUT_TOKENS_GEMINI,
         safety_settings=SAFETY_SETTINGS,
         response_mime_type=model_kwargs.get("response_mime_type", "text/plain") if model_kwargs else "text/plain",
+        response_schema=model_kwargs.get("response_schema", None) if model_kwargs else None,
     )
 
     formatted_messages = [gtypes.Content(role=message.role, parts=message.content) for message in messages]

src/khoj/routers/helpers.py

@@ -1129,6 +1129,7 @@ async def send_message_to_model_wrapper(
     query: str,
     system_message: str = "",
     response_type: str = "text",
+    response_schema: BaseModel = None,
     deepthought: bool = False,
     user: KhojUser = None,
     query_images: List[str] = None,
@@ -1256,6 +1257,7 @@ async def send_message_to_model_wrapper(
             api_key=api_key,
             model=chat_model_name,
             response_type=response_type,
+            response_schema=response_schema,
             tracer=tracer,
         )
     else:
@@ -1266,6 +1268,7 @@ def send_message_to_model_wrapper_sync(
     message: str,
     system_message: str = "",
     response_type: str = "text",
+    response_schema: BaseModel = None,
     user: KhojUser = None,
     query_images: List[str] = None,
     query_files: str = "",
@@ -1372,6 +1375,7 @@ def send_message_to_model_wrapper_sync(
             api_key=api_key,
             model=chat_model_name,
             response_type=response_type,
+            response_schema=response_schema,
             tracer=tracer,
         )
     else: