adding support for claude code routing (#575)

* fixed for claude code routing. first commit

* removing redundant enum tags for cache_control

* making sure that claude code can run via the archgw cli

* fixing broken config

* adding a README.md and updated the cli to use more of our defined patterns for params

* fixed config.yaml

* minor fixes to make sure PR is clean. Ready to ship

* adding claude-sonnet-4-5 to the config

* fixes based on PR

* fixed alias for README

* fixed 400 error handling tests, now that we write temperature to 1.0 for GPT-5

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-257.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-288.local>

demos/use_cases/claude_code/config.yaml

@@ -0,0 +1,41 @@
+version: v0.1
+
+listeners:
+  egress_traffic:
+    address: 0.0.0.0
+    port: 12000
+    message_format: openai
+    timeout: 30s
+
+llm_providers:
+  # OpenAI Models
+  - model: openai/gpt-5-2025-08-07
+    access_key: $OPENAI_API_KEY
+    routing_preferences:
+      - name: code generation
+        description: generating new code snippets, functions, or boilerplate based on user prompts or requirements
+
+  - model: openai/gpt-4.1-2025-04-14
+    access_key: $OPENAI_API_KEY
+    routing_preferences:
+      - name: code understanding
+        description: understand and explain existing code snippets, functions, or libraries
+
+  # Anthropic Models
+  - model: anthropic/claude-sonnet-4-5
+    default: true
+    access_key: $ANTHROPIC_API_KEY
+
+  - model: anthropic/claude-3-haiku-20240307
+    access_key: $ANTHROPIC_API_KEY
+
+  # Ollama Models
+  - model: ollama/llama3.1
+    base_url: http://host.docker.internal:11434
+
+
+# Model aliases - friendly names that map to actual provider names
+model_aliases:
+  # Alias for a small faster Claude model
+  arch.claude.code.small.fast:
+    target: claude-3-haiku-20240307