Implemented phase 4 for the POC prototype in the Website service.

Services/Website/Sources/Library/Public/Extensions/ConfigKey+Constants.swift

@@ -99,6 +99,11 @@ extension ConfigKey {
         public static let strictTransportSecurity: ConfigKey = "security.strictTransportSecurity"
     }
     /// A namespace for the site configuration keys.
+    /// A namespace for the passkey configuration keys.
+    public enum Passkeys {
+        /// The configuration key for the origin the sign-in screen is served at, which passkeys are bound to.
+        public static let origin: ConfigKey = "passkeys.origin"
+    }
     public enum Site {
         /// The configuration key for the public origin the site is served at (scheme and host, no trailing slash).
         public static let origin: ConfigKey = "site.origin"

Services/Website/Sources/Library/Public/Extensions/String+Constants.swift

@@ -44,6 +44,13 @@ extension String {
         /// The TLS token requiring TLS.
         public static let tlsRequire = "require"
     }
+    /// A namespace for the passkey default configuration values.
+    public enum Passkeys {
+        /// The default origin passkeys are bound to: where the service answers when run locally.
+        ///
+        /// A deployment sets `passkeys.origin` to its own origin. Browsers only run WebAuthn on HTTPS or on `localhost` — not on `127.0.0.1`.
+        public static let origin = "http://localhost:8080"
+    }
     /// A namespace for well-known path string constants.
     public enum Path {
         /// The directory, relative to the working directory, that the website's static files are served from.