feat(setup): ensure proxy key validation runs after credential creation

Delay mandatory PROXY_API_KEY validation until the server runtime block to facilitate initial environment setup.

This adjustment allows the application to proceed with the `--add-credential` flow even if the proxy key is initially unset:
- Imports and runs `ensure_env_defaults()` to generate missing keys or files.
- Reloads environment variables (dotenv) immediately after generation.
- Validates the PROXY_API_KEY only before starting uvicorn.

Also adds support for CHUTES_API_KEY in the credential tool.

src/proxy_app/main.py

@@ -133,8 +133,7 @@ ENABLE_REQUEST_LOGGING = args.enable_request_logging
 if ENABLE_REQUEST_LOGGING:
     logging.info("Request logging is enabled.")
 PROXY_API_KEY = os.getenv("PROXY_API_KEY")
-if not PROXY_API_KEY:
-    raise ValueError("PROXY_API_KEY environment variable not set.")
+# Note: PROXY_API_KEY validation moved to server startup to allow credential tool to run first
 
 # Discover API keys from environment variables
 api_keys = {}
@@ -713,7 +712,15 @@ async def token_count(
 
 if __name__ == "__main__":
     if args.add_credential:
+        # Import and call ensure_env_defaults to create .env and PROXY_API_KEY if needed
+        from rotator_library.credential_tool import ensure_env_defaults
+        ensure_env_defaults()
+        # Reload environment variables after ensure_env_defaults creates/updates .env
+        load_dotenv(override=True)
         run_credential_tool()
     else:
+        # Validate PROXY_API_KEY before starting the server
+        if not PROXY_API_KEY:
+            raise ValueError("PROXY_API_KEY environment variable not set. Please run with --add-credential to set up your environment.")
         import uvicorn
         uvicorn.run(app, host=args.host, port=args.port)

src/rotator_library/credential_tool.py

@@ -47,7 +47,8 @@ async def setup_api_key():
         "OpenAI": "OPENAI_API_KEY", "Anthropic": "ANTHROPIC_API_KEY",
         "Google AI Studio (Gemini)": "GEMINI_API_KEY", "Azure OpenAI": "AZURE_API_KEY",
         "Vertex AI": "GOOGLE_API_KEY", "AWS Bedrock": "AWS_ACCESS_KEY_ID",
-        "Cohere": "COHERE_API_KEY", "Mistral AI": "MISTRAL_API_KEY",
+        "Cohere": "COHERE_API_KEY", "Chutes": "CHUTES_API_KEY",
+        "Mistral AI": "MISTRAL_API_KEY",
         "Codestral (Mistral)": "CODESTRAL_API_KEY", "Groq": "GROQ_API_KEY",
         "Perplexity": "PERPLEXITYAI_API_KEY", "xAI": "XAI_API_KEY",
         "Together AI": "TOGETHERAI_API_KEY", "Fireworks AI": "FIREWORKS_AI_API_KEY",