feat: Begins htmx integration

Sources/ViewController/Views/MainPage.swift

@@ -28,6 +28,7 @@ struct MainPage<Inner: HTML>: SendableHTMLDocument where Inner: Sendable {
       .init(name: "sizes", value: "180x180")
     )
     link(.rel(.init(rawValue: "mainifest")), .href("/site.webmanifest"))
+    script(.src("https://unpkg.com/htmx.org@2.0.4")) {}
   }
 
   var body: some HTML {
@@ -59,7 +60,10 @@ private struct Header: HTML {
         // TODO: Add class active, to button that is the active route.
         ul(.class("flex flex-wrap gap-x-2 lg:gap-x-5 \(text: .yellow) font-bold")) {
           li {
-            a(.href(route: .moldRisk(.index)), .class("hover:border-b \(border: .yellow)")) {
+            a(
+              .class("hover:border-b \(border: .yellow)"),
+              .hx.get(route: .moldRisk(.index)), .hx.target("#content"), .hx.pushURL(true)
+            ) {
               "Mold-Risk"
             }
           }
@@ -80,7 +84,9 @@ private struct PageContent<Body: HTML>: HTML where Body: Sendable {
   var content: some HTML {
     div(.class("mx-5 lg:mx-20")) {
       div(.class("rounded-xl shadow-lg bg-white dark:bg-slate-700 p-8")) {
-        body()
+        div(.id("content")) {
+          body()
+        }
       }
     }
   }