feat: Begins adding climate zone client and location clients.

Sources/CoreModels/DesignTemperatures.swift

@@ -0,0 +1,11 @@
+/// Represents design temperature conditions.
+public struct DesignTemperatures: Codable, Equatable, Sendable {
+
+  public let cooling: Double
+  public let heating: Double
+
+  public init(cooling: Double, heating: Double) {
+    self.cooling = cooling
+    self.heating = heating
+  }
+}