add support for v1/messages and transformations (#558)

* pushing draft PR

* transformations are working. Now need to add some tests next

* updated tests and added necessary response transformations for Anthropics' message response object

* fixed bugs for integration tests

* fixed doc tests

* fixed serialization issues with enums on response

* adding some debug logs to help

* fixed issues with non-streaming responses

* updated the stream_context to update response bytes

* the serialized bytes length must be set in the response side

* fixed the debug statement that was causing the integration tests for wasm to fail

* fixing json parsing errors

* intentionally removing the headers

* making sure that we convert the raw bytes to the correct provider type upstream

* fixing non-streaming responses to tranform correctly

* /v1/messages works with transformations to and from /v1/chat/completions

* updating the CLI and demos to support anthropic vs. claude

* adding the anthropic key to the preference based routing tests

* fixed test cases and added more structured logs

* fixed integration tests and cleaned up logs

* added python client tests for anthropic and openai

* cleaned up logs and fixed issue with connectivity for llm gateway in weather forecast demo

* fixing the tests. python dependency order was broken

* updated the openAI client to fix demos

* removed the raw response debug statement

* fixed the dup cloning issue and cleaned up the ProviderRequestType enum and traits

* fixing logs

* moved away from string literals to consts

* fixed streaming from Anthropic Client to OpenAI

* removed debug statement that would likely trip up integration tests

* fixed integration tests for llm_gateway

* cleaned up test cases and removed unnecessary crates

* fixing comments from PR

* fixed bug whereby we were sending an OpenAIChatCompletions request object to llm_gateway even though the request may have been AnthropicMessages

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-4.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-9.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-10.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-41.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-136.local>

demos/samples_python/weather_forecast/arch_config.yaml

@@ -7,6 +7,12 @@ listeners:
     message_format: openai
     timeout: 30s
 
+  egress_traffic:
+    address: 0.0.0.0
+    port: 12000
+    message_format: openai
+    timeout: 30s
+
 endpoints:
   weather_forecast_service:
     endpoint: host.docker.internal:18083
@@ -24,6 +30,12 @@ llm_providers:
     model: openai/gpt-4o
     default: true
 
+  - access_key: $OPENAI_API_KEY
+    model: openai/gpt-4o-mini
+
+  - access_key: $ANTHROPIC_API_KEY
+    model: anthropic/claude-sonnet-4-20250514
+
 system_prompt: |
   You are a helpful assistant.