feat: Update Claude models to Opus 4.1 and Sonnet 4.1

This commit updates all references to Claude Opus 4 and Sonnet 4 to their newer 4.1 versions throughout the codebase.

The changes include:
- Updating model names in `conf/custom_models.json` and `providers/dial.py`.
- Updating aliases and descriptions to match the new model versions.
- Updating `.env.example` to reflect the new model names.
- Updating all relevant test suites to use the new model names and ensure all tests pass.

tests/test_openrouter_registry.py

@@ -87,9 +87,9 @@ class TestOpenRouterModelRegistry:
 
         # Test various aliases
         test_cases = [
-            ("opus", "anthropic/claude-opus-4"),
-            ("OPUS", "anthropic/claude-opus-4"),  # Case insensitive
-            ("claude", "anthropic/claude-sonnet-4"),
+            ("opus", "anthropic/claude-opus-4.1"),
+            ("OPUS", "anthropic/claude-opus-4.1"),  # Case insensitive
+            ("claude", "anthropic/claude-sonnet-4.1"),
             ("o3", "openai/o3"),
             ("deepseek", "deepseek/deepseek-r1-0528"),
             ("mistral", "mistralai/mistral-large-2411"),
@@ -105,9 +105,9 @@ class TestOpenRouterModelRegistry:
         registry = OpenRouterModelRegistry()
 
         # Should be able to look up by full model name
-        config = registry.resolve("anthropic/claude-opus-4")
+        config = registry.resolve("anthropic/claude-opus-4.1")
         assert config is not None
-        assert config.model_name == "anthropic/claude-opus-4"
+        assert config.model_name == "anthropic/claude-opus-4.1"
 
         config = registry.resolve("openai/o3")
         assert config is not None
@@ -131,8 +131,8 @@ class TestOpenRouterModelRegistry:
 
         # Registry now returns ModelCapabilities objects directly
         assert config.provider == ProviderType.OPENROUTER
-        assert config.model_name == "anthropic/claude-opus-4"
-        assert config.friendly_name == "OpenRouter (anthropic/claude-opus-4)"
+        assert config.model_name == "anthropic/claude-opus-4.1"
+        assert config.friendly_name == "OpenRouter (anthropic/claude-opus-4.1)"
         assert config.context_window == 200000
         assert not config.supports_extended_thinking