feat: Adds hydronic system pressure calculator.

Sources/Routes/Models/HydronicSystemPressure.swift

@@ -0,0 +1,84 @@
+import CasePaths
+import PsychrometricClient
+@preconcurrency import URLRouting
+
+//
+public enum HydronicSystemPressure {
+
+  public static let description = """
+  Calculate the required hydronic system pressure based on height of a building.
+  """
+
+  public struct Request: Codable, Equatable, Hashable, Sendable {
+    public let height: Double
+    public let waterTemperature: Double?
+
+    public init(height: Double, waterTemperature: Double? = nil) {
+      self.height = height
+      self.waterTemperature = waterTemperature
+    }
+
+    public enum FieldKey: String, CaseIterable {
+      case height
+      case waterTemperature
+    }
+  }
+
+  public struct Response: Codable, Equatable, Sendable {
+
+    public let pressure: Double
+    public let waterDensity: DensityOf<Water>
+    public let warnings: [String]
+
+    public init(pressure: Double, waterDensity: DensityOf<Water>, warnings: [String]) {
+      self.pressure = pressure
+      self.waterDensity = waterDensity
+      self.warnings = warnings
+    }
+  }
+}
+
+// MARK: - Router
+
+public extension SiteRoute.View {
+
+  enum HydronicSystemPressure: Equatable, Hashable, Sendable {
+    case index
+    case submit(Routes.HydronicSystemPressure.Request)
+
+    typealias Key = Routes.HydronicSystemPressure.Request.FieldKey
+    static let rootPath = "hydronic-system-pressure"
+
+    public static let router = OneOf {
+      Route(.case(Self.index)) {
+        Path { rootPath }
+        Method.get
+      }
+      Route(.case(Self.submit)) {
+        Path { rootPath }
+        Method.post
+        Body {
+          FormData {
+            Field(Key.height) { Double.parser() }
+            Optionally { Field(Key.waterTemperature) { Double.parser() } }
+          }
+          .map(.memberwise(Routes.HydronicSystemPressure.Request.init))
+        }
+      }
+    }
+  }
+
+}
+
+#if DEBUG
+  public extension HydronicSystemPressure.Response {
+    static let mock = Self(
+      pressure: 15,
+      waterDensity: 62.37,
+      warnings: [
+        "Water density based on 60 water - include water temperature for more accurate result."
+      ]
+    )
+  }
+
+#endif