Add initial project structure and configuration files

- Created .gitignore to exclude unnecessary files and directories.
- Added Cargo.toml for Rust workspace configuration.
- Introduced example configuration file entropix.yaml.example for user customization.
- Included LICENSE file with Apache 2.0 license details.
- Created pyproject.toml for Python project metadata and dependencies.
- Added README.md with project overview and usage instructions.
- Implemented a broken agent example to demonstrate testing capabilities.
- Established Rust module structure with Cargo.toml and source files.
- Set up initial tests for assertions and configuration validation.

tests/test_config.py

@@ -0,0 +1,181 @@
+"""
+Tests for configuration loading and validation.
+"""
+
+import pytest
+from pathlib import Path
+import tempfile
+
+from entropix.core.config import (
+    EntropixConfig,
+    AgentConfig,
+    ModelConfig,
+    MutationConfig,
+    InvariantConfig,
+    OutputConfig,
+    load_config,
+    create_default_config,
+    AgentType,
+    MutationType,
+    InvariantType,
+    OutputFormat,
+)
+
+
+class TestEntropixConfig:
+    """Tests for EntropixConfig."""
+    
+    def test_create_default_config(self):
+        """Test creating a default configuration."""
+        config = create_default_config()
+        
+        assert config.version == "1.0"
+        assert config.agent.type == AgentType.HTTP
+        assert config.model.provider == "ollama"
+        assert config.model.name == "qwen3:8b"
+        assert len(config.golden_prompts) >= 1
+    
+    def test_config_to_yaml(self):
+        """Test serializing config to YAML."""
+        config = create_default_config()
+        yaml_str = config.to_yaml()
+        
+        assert "version" in yaml_str
+        assert "agent" in yaml_str
+        assert "golden_prompts" in yaml_str
+    
+    def test_config_from_yaml(self):
+        """Test parsing config from YAML."""
+        yaml_content = """
+version: "1.0"
+agent:
+  endpoint: "http://localhost:8000/test"
+  type: "http"
+  timeout: 5000
+model:
+  provider: "ollama"
+  name: "qwen3:8b"
+golden_prompts:
+  - "Test prompt 1"
+  - "Test prompt 2"
+invariants:
+  - type: "latency"
+    max_ms: 1000
+"""
+        config = EntropixConfig.from_yaml(yaml_content)
+        
+        assert config.agent.endpoint == "http://localhost:8000/test"
+        assert config.agent.timeout == 5000
+        assert len(config.golden_prompts) == 2
+        assert len(config.invariants) == 1
+    
+    def test_load_config_file_not_found(self):
+        """Test loading a non-existent config file."""
+        with pytest.raises(FileNotFoundError):
+            load_config("/nonexistent/path/config.yaml")
+    
+    def test_load_config_from_file(self):
+        """Test loading config from an actual file."""
+        yaml_content = """
+version: "1.0"
+agent:
+  endpoint: "http://test:8000/invoke"
+golden_prompts:
+  - "Hello world"
+"""
+        with tempfile.NamedTemporaryFile(
+            mode="w", suffix=".yaml", delete=False
+        ) as f:
+            f.write(yaml_content)
+            f.flush()
+            
+            config = load_config(f.name)
+            assert config.agent.endpoint == "http://test:8000/invoke"
+            
+            # Cleanup
+            Path(f.name).unlink()
+
+
+class TestAgentConfig:
+    """Tests for AgentConfig validation."""
+    
+    def test_valid_http_config(self):
+        """Test valid HTTP agent config."""
+        config = AgentConfig(
+            endpoint="http://localhost:8000/invoke",
+            type=AgentType.HTTP,
+            timeout=30000,
+        )
+        assert config.endpoint == "http://localhost:8000/invoke"
+    
+    def test_timeout_bounds(self):
+        """Test timeout validation."""
+        # Valid
+        config = AgentConfig(endpoint="http://test", timeout=1000)
+        assert config.timeout == 1000
+        
+        # Too low
+        with pytest.raises(ValueError):
+            AgentConfig(endpoint="http://test", timeout=500)
+    
+    def test_env_var_expansion(self):
+        """Test environment variable expansion in headers."""
+        import os
+        os.environ["TEST_API_KEY"] = "secret123"
+        
+        config = AgentConfig(
+            endpoint="http://test",
+            headers={"Authorization": "Bearer ${TEST_API_KEY}"},
+        )
+        
+        assert config.headers["Authorization"] == "Bearer secret123"
+        
+        del os.environ["TEST_API_KEY"]
+
+
+class TestMutationConfig:
+    """Tests for MutationConfig."""
+    
+    def test_default_mutation_types(self):
+        """Test default mutation types are set."""
+        config = MutationConfig()
+        
+        assert MutationType.PARAPHRASE in config.types
+        assert MutationType.NOISE in config.types
+        assert MutationType.PROMPT_INJECTION in config.types
+    
+    def test_mutation_weights(self):
+        """Test mutation weights."""
+        config = MutationConfig()
+        
+        # Prompt injection should have higher weight
+        assert config.weights[MutationType.PROMPT_INJECTION] > config.weights[MutationType.NOISE]
+
+
+class TestInvariantConfig:
+    """Tests for InvariantConfig validation."""
+    
+    def test_latency_invariant(self):
+        """Test latency invariant requires max_ms."""
+        config = InvariantConfig(type=InvariantType.LATENCY, max_ms=2000)
+        assert config.max_ms == 2000
+    
+    def test_latency_missing_max_ms(self):
+        """Test latency invariant fails without max_ms."""
+        with pytest.raises(ValueError):
+            InvariantConfig(type=InvariantType.LATENCY)
+    
+    def test_contains_invariant(self):
+        """Test contains invariant requires value."""
+        config = InvariantConfig(type=InvariantType.CONTAINS, value="test")
+        assert config.value == "test"
+    
+    def test_similarity_invariant(self):
+        """Test similarity invariant."""
+        config = InvariantConfig(
+            type=InvariantType.SIMILARITY,
+            expected="Expected response",
+            threshold=0.8,
+        )
+        assert config.threshold == 0.8
+