Add Windows call model

Author: mearvk

src/windows/WindowsCall.java

@@ -0,0 +1,16 @@
+package windows;
+
+import java.time.Instant;
+
+/** Immutable record of a requested Windows operation. */
+public record WindowsCall(
+        String id,
+        WindowsCitizen citizen,
+        WindowsProgram program,
+        WindowsDirective directive,
+        Instant requestedAt) {
+    public WindowsCall {
+        if (id == null || id.isBlank()) throw new IllegalArgumentException("id is required");
+        if (requestedAt == null) throw new IllegalArgumentException("requestedAt is required");
+    }
+}