WIP: Working signup and login forms, along with initial view auth middleware.

Sources/ViewController/Interface.swift

@@ -15,6 +15,10 @@ public typealias AnySendableHTML = (any HTML & Sendable)
 
 @DependencyClient
 public struct ViewController: Sendable {
+
+  public typealias AuthenticateHandler = @Sendable (User) -> Void
+  public typealias CurrentUserHandler = @Sendable () throws -> User
+
   public var view: @Sendable (Request) async throws -> AnySendableHTML
 }
 
@@ -25,15 +29,25 @@ extension ViewController {
     public let route: SiteRoute.View
     public let isHtmxRequest: Bool
     public let logger: Logger
+    public let authenticateUser: AuthenticateHandler
+    public let currentUser: CurrentUserHandler
 
     public init(
       route: SiteRoute.View,
       isHtmxRequest: Bool,
-      logger: Logger
+      logger: Logger,
+      authenticateUser: @escaping AuthenticateHandler,
+      currentUser: @escaping CurrentUserHandler
     ) {
       self.route = route
       self.isHtmxRequest = isHtmxRequest
       self.logger = logger
+      self.authenticateUser = authenticateUser
+      self.currentUser = currentUser
+    }
+
+    func authenticate(_ user: User) {
+      self.authenticateUser(user)
     }
   }
 }