Implemented phase 0 for the POC prototype in the Website service.

Services/Website/Sources/Library/Internal/Enumerations/Format.swift

@@ -0,0 +1,34 @@
+/// A format listings are published in, declared in navigation order; the raw value is the search filter token.
+enum Format: String, CaseIterable, Sendable {
+    /// Single-issue comics.
+    case singleIssues = "single-issues"
+    /// Manga volumes.
+    case manga
+    /// Trade paperbacks.
+    case tradePaperbacks = "trade-paperbacks"
+    /// Hardcovers.
+    case hardcovers
+}
+
+// MARK: - Extensions
+
+extension Format {
+
+    // MARK: Computed
+
+    /// The format's name as shown in the navigation.
+    var label: String {
+        switch self {
+        case .singleIssues: "Single issues"
+        case .manga: "Manga"
+        case .tradePaperbacks: "Trade paperbacks"
+        case .hardcovers: "Hardcovers"
+        }
+    }
+
+    /// The path of the search screen filtered to the format.
+    var path: String {
+        "\(String.Route.search)?format=\(rawValue)"
+    }
+
+}