Added tons of opcode documentation, changed license to ISC and a lot of file refactoring.

src/vm/to_number.c

@@ -1,3 +1,36 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the ISC license.
+ * https://opensource.org/license/isc-license-txt
+ */
+
+/**
+* @file to_number.c
+ * @brief Implements the OP_TO_NUMBER opcode for converting values to integers in the VM.
+ *
+ * This file handles the OP_TO_NUMBER instruction, which converts a value to an integer.
+ * The value is popped from the stack, and the result is pushed back.
+ *
+ * Behavior:
+ * - Pops the value from the stack.
+ * - Converts the value to an integer.
+ * - Pushes the result onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the conversion fails.
+ *
+ * Example:
+ * // Bytecode: OP_TO_NUMBER
+ * // Stack before: ["42"]
+ * // Stack after: [42]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_TO_NUMBER: {
     Value v = pop_value(vm);
     if (v.type == VAL_INT) {