feat: Adds hydronic system pressure calculator.

Sources/Styleguide/SVG.swift

@@ -45,6 +45,7 @@ public struct SVGSize: Sendable {
 public enum SVGType: Sendable, CaseIterable {
   case calculator
   case checkCircle
+  case circleGauge
   case droplets
   case exclamation
   case funnel
@@ -63,6 +64,7 @@ public enum SVGType: Sendable, CaseIterable {
     switch self {
     case .calculator: return calculatorSvg(size: size)
     case .checkCircle: return checkCircleSvg(size: size)
+    case .circleGauge: return circleGaugeSvg(size: size)
     case .droplets: return dropletsSvg(size: size)
     case .exclamation: return exclamationSvg(size: size)
     case .funnel: return funnelSvg(size: size)
@@ -84,6 +86,16 @@ public enum SVGType: Sendable, CaseIterable {
 
 // swiftlint:disable line_length
 
+private func circleGaugeSvg(size: SVGSize) -> HTMLRaw {
+  HTMLRaw("""
+  <svg xmlns="http://www.w3.org/2000/svg" width="\(size.width)" height="\(size.height)" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-circle-gauge">
+  <path d="M15.6 2.7a10 10 0 1 0 5.7 5.7"/>
+  <circle cx="12" cy="12" r="2"/>
+  <path d="M13.4 10.6 19 5"/>
+  </svg>
+  """)
+}
+
 private func scaleSvg(size: SVGSize) -> HTMLRaw {
   HTMLRaw("""
   <svg xmlns="http://www.w3.org/2000/svg" width="\(size.width)" height="\(size.height)" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-scale">