Align with MCP semantic conventions for span naming and structure
- Added ParsedLogEntry enum with McpTool and Chat variants
- MCP tool spans now follow format: tools/call {tool_name} with gen_ai.operation.name=execute_tool
- Chat spans use name: 'chat' for assistant messages
- SpanDisplay now uses attributes as Map (mirrors OTLP export)
- Removed duplicate fields - all data now in attributes map
- Updated validate.rs and info.rs to work with new enum structure
- Tool arguments/result serialized as JSON strings for OTLP compatibility