fix: implement AZURE_RESOURCE_NAME config for Azure OpenAI (#213)

Previously AZURE_RESOURCE_NAME was documented in env.example but not
actually used in the code. This caused Azure OpenAI configuration to fail
when users set AZURE_RESOURCE_NAME instead of AZURE_BASE_URL.

Changes:
- Read AZURE_RESOURCE_NAME from environment and pass to createAzure()
- resourceName constructs endpoint: https://{name}.openai.azure.com/openai/v1
- baseURL takes precedence over resourceName when both are set
- Updated env.example with clearer documentation

Fixes #208

env.example

@@ -41,9 +41,13 @@ AI_MODEL=global.anthropic.claude-sonnet-4-5-20250929-v1:0
 # GOOGLE_THINKING_LEVEL=high                 # Optional: Gemini 3 thinking level (low/high)
 
 # Azure OpenAI Configuration
+# Configure endpoint using ONE of these methods:
+#   1. AZURE_RESOURCE_NAME - SDK constructs: https://{name}.openai.azure.com/openai/v1{path}
+#   2. AZURE_BASE_URL - SDK appends /v1{path} to your URL
+# If both are set, AZURE_BASE_URL takes precedence.
 # AZURE_RESOURCE_NAME=your-resource-name
 # AZURE_API_KEY=...
-# AZURE_BASE_URL=https://your-resource.openai.azure.com  # Optional: Custom endpoint (overrides resourceName)
+# AZURE_BASE_URL=https://your-resource.openai.azure.com/openai  # Alternative: Custom endpoint
 # AZURE_REASONING_EFFORT=low                 # Optional: Azure reasoning effort (low, medium, high)
 # AZURE_REASONING_SUMMARY=detailed