Rename the project from "MyLibrary" to "MedicalLib" to better reflect its intended purpose as a library for medical simulations.

- Rename all files, directories, and internal project names to "MedicalLib".
- Replace the generic `add` function with a more domain-specific `calculateBMI` function as an initial example of the library's capabilities.
- Update the `AGENTS.md` file to describe the new purpose and scope of the MedicalLib library.

src/Library.cpp

@@ -1,5 +0,0 @@
-#include "Library.h"
-
-int add(int a, int b) {
-    return a + b;
-}

src/Library.h

@@ -1,15 +0,0 @@
-#pragma once
-
-// Define MY_LIB_EXPORT for exporting symbols from the DLL
-#if defined(_WIN32)
-    #if defined(MY_LIB_EXPORT)
-        #define MY_LIB_API __declspec(dllexport)
-    #else
-        #define MY_LIB_API __declspec(dllimport)
-    #endif
-#else
-    #define MY_LIB_API
-#endif
-
-// A simple function to be exported
-MY_LIB_API int add(int a, int b);

src/MedicalLib.cpp

@@ -0,0 +1,12 @@
+#include "MedicalLib/MedicalLib.h"
+#include <stdexcept>
+
+double calculateBMI(double weight_kg, double height_m) {
+    if (height_m <= 0) {
+        throw std::invalid_argument("Height must be positive.");
+    }
+    if (weight_kg <= 0) {
+        throw std::invalid_argument("Weight must be positive.");
+    }
+    return weight_kg / (height_m * height_m);
+}