feat: Update Claude model references from v3 to v4 (fixes issue #118) (#119)

* feat: Update Claude model references from v3 to v4

- Update model configurations from claude-3-opus to claude-4-opus
- Update model configurations from claude-3-sonnet to claude-4-sonnet
- Maintain backward compatibility through existing aliases (opus, sonnet, claude)
- Update provider registry preferred models list
- Update all test cases and assertions to reflect new model names
- Update documentation and examples consistently across all files
- Add Claude 4 model support while preserving existing functionality

Files modified: 15 (config, docs, providers, tests, tools)
Pattern: Systematic claude-3-* → claude-4-* model reference migration

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* PR feedback: changed anthropic/claude-4-opus -> anthropic/claude-opus-4 and anthropic/claude-4-haiku -> anthropic/claude-3.5-haiku

* changed anthropic/claude-4-sonnet -> anthropic/claude-sonnet-4

* PR feedback removed specific model from test mock

* PR feedback removed base.py

---------

Co-authored-by: Omry Nachman <omry@wix.com>
Co-authored-by: Claude <noreply@anthropic.com>

tests/test_openrouter_registry.py

@@ -74,9 +74,9 @@ class TestOpenRouterModelRegistry:
 
         # Test various aliases
         test_cases = [
-            ("opus", "anthropic/claude-3-opus"),
-            ("OPUS", "anthropic/claude-3-opus"),  # Case insensitive
-            ("claude", "anthropic/claude-3-sonnet"),
+            ("opus", "anthropic/claude-opus-4"),
+            ("OPUS", "anthropic/claude-opus-4"),  # Case insensitive
+            ("claude", "anthropic/claude-sonnet-4"),
             ("o3", "openai/o3"),
             ("deepseek", "deepseek/deepseek-r1-0528"),
             ("mistral", "mistralai/mistral-large-2411"),
@@ -92,9 +92,9 @@ class TestOpenRouterModelRegistry:
         registry = OpenRouterModelRegistry()
 
         # Should be able to look up by full model name
-        config = registry.resolve("anthropic/claude-3-opus")
+        config = registry.resolve("anthropic/claude-opus-4")
         assert config is not None
-        assert config.model_name == "anthropic/claude-3-opus"
+        assert config.model_name == "anthropic/claude-opus-4"
 
         config = registry.resolve("openai/o3")
         assert config is not None
@@ -118,7 +118,7 @@ class TestOpenRouterModelRegistry:
 
         caps = config.to_capabilities()
         assert caps.provider == ProviderType.OPENROUTER
-        assert caps.model_name == "anthropic/claude-3-opus"
+        assert caps.model_name == "anthropic/claude-opus-4"
         assert caps.friendly_name == "OpenRouter"
         assert caps.context_window == 200000
         assert not caps.supports_extended_thinking