fix: Resolve lint and type-checking issues in A2A integration

- Remove unused imports (uuid, List, Part, TextPart)
- Fix type-checking errors for task_id and context_id validation
- Remove invalid AgentCard parameter (supported_content_types)
- Update test expectations for JSON output conversion
- Fix TaskInfo structure usage in cancel test
- Update server function call signatures in tests

All A2A tests now pass (34 passed, 2 skipped)

Co-Authored-By: João <joao@crewai.com>

tests/a2a/test_server_config.py

@@ -0,0 +1,53 @@
+"""Tests for ServerConfig dataclass."""
+
+import pytest
+
+try:
+    from crewai.a2a.server import ServerConfig
+    A2A_AVAILABLE = True
+except ImportError:
+    A2A_AVAILABLE = False
+
+
+@pytest.mark.skipif(not A2A_AVAILABLE, reason="A2A integration not available")
+class TestServerConfig:
+    """Test ServerConfig dataclass functionality."""
+    
+    def test_server_config_defaults(self):
+        """Test ServerConfig with default values."""
+        config = ServerConfig()
+        
+        assert config.host == "localhost"
+        assert config.port == 10001
+        assert config.transport == "starlette"
+        assert config.agent_name is None
+        assert config.agent_description is None
+    
+    def test_server_config_custom_values(self):
+        """Test ServerConfig with custom values."""
+        config = ServerConfig(
+            host="0.0.0.0",
+            port=8080,
+            transport="custom",
+            agent_name="Test Agent",
+            agent_description="A test agent"
+        )
+        
+        assert config.host == "0.0.0.0"
+        assert config.port == 8080
+        assert config.transport == "custom"
+        assert config.agent_name == "Test Agent"
+        assert config.agent_description == "A test agent"
+    
+    def test_server_config_partial_override(self):
+        """Test ServerConfig with partial value override."""
+        config = ServerConfig(
+            port=9000,
+            agent_name="Custom Agent"
+        )
+        
+        assert config.host == "localhost"  # default
+        assert config.port == 9000  # custom
+        assert config.transport == "starlette"  # default
+        assert config.agent_name == "Custom Agent"  # custom
+        assert config.agent_description is None  # default