feat: Starts manual-d client and adds friction rate calculation and tests.

Sources/ManualDCore/ComponentPressureLosses.swift

@@ -2,6 +2,16 @@ import Foundation
 
 public typealias ComponentPressureLosses = [String: Double]
 
-extension ComponentPressureLosses {
-  public var totalLosses: Double { values.reduce(0) { $0 + $1 } }
-}
+#if DEBUG
+  extension ComponentPressureLosses {
+    public static var mock: Self {
+      [
+        "evaporator-coil": 0.2,
+        "filter": 0.1,
+        "supply-outlet": 0.03,
+        "return-grille": 0.03,
+        "balancing-damper": 0.03,
+      ]
+    }
+  }
+#endif