Watch app MVP: XcodeGen project, gateway client, pair, feed, thread, new thread, notifications

SwiftUI watch-only app in watch/, generated by XcodeGen. Codable models mirror
gateway/src/contract.ts, with lenient string enums so new phases or decisions
still decode. A DemoGateway serves fixtures from the docs/api.md examples for
previews and demo mode. Swift Testing covers decoding the documented JSON,
request encoding, notification action parsing and the small view helpers.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

watch/WristCode/Auth/DeviceStore.swift

@@ -0,0 +1,94 @@
+// The device token and gateway URL, kept in the Keychain. They are readable after first unlock, so
+// a notification action handled in the background can still call the gateway.
+
+import Foundation
+import Security
+
+struct Credentials: Equatable, Sendable {
+    var gatewayURL: URL
+    var token: String
+}
+
+enum DeviceStore {
+    static let defaultGatewayURL = "https://wristcode.gbrown.org"
+
+    private static let service = "org.gbrown.wristcode"
+    private static let tokenAccount = "deviceToken"
+    private static let urlAccount = "gatewayURL"
+
+    static func load() -> Credentials? {
+        guard let token = read(tokenAccount),
+              let urlString = read(urlAccount),
+              let url = URL(string: urlString)
+        else { return nil }
+        return Credentials(gatewayURL: url, token: token)
+    }
+
+    static func save(_ credentials: Credentials) {
+        write(credentials.gatewayURL.absoluteString, account: urlAccount)
+        write(credentials.token, account: tokenAccount)
+    }
+
+    /// Forgets the token but keeps the URL, so the pairing screen is prefilled.
+    static func clearToken() {
+        delete(tokenAccount)
+    }
+
+    /// The last gateway URL used, for prefilling the pairing screen.
+    static var lastGatewayURL: String {
+        read(urlAccount) ?? defaultGatewayURL
+    }
+
+    /// Turns what someone typed into a gateway base URL: trims it, adds `https://` when there is
+    /// no scheme, and drops trailing slashes. Returns nil when it is not a usable URL.
+    static func normalizeGatewayURL(_ input: String) -> URL? {
+        var text = input.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !text.isEmpty else { return nil }
+        if !text.contains("://") { text = "https://" + text }
+        while text.hasSuffix("/") { text.removeLast() }
+        guard let components = URLComponents(string: text),
+              let scheme = components.scheme?.lowercased(),
+              scheme == "https" || scheme == "http",
+              let host = components.host, !host.isEmpty
+        else { return nil }
+        return components.url
+    }
+
+    // MARK: - Keychain
+
+    private static func query(_ account: String) -> [String: Any] {
+        [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account,
+        ]
+    }
+
+    private static func read(_ account: String) -> String? {
+        var query = query(account)
+        query[kSecReturnData as String] = true
+        query[kSecMatchLimit as String] = kSecMatchLimitOne
+        var result: CFTypeRef?
+        guard SecItemCopyMatching(query as CFDictionary, &result) == errSecSuccess,
+              let data = result as? Data
+        else { return nil }
+        return String(data: data, encoding: .utf8)
+    }
+
+    private static func write(_ value: String, account: String) {
+        let data = Data(value.utf8)
+        let attributes: [String: Any] = [
+            kSecValueData as String: data,
+            kSecAttrAccessible as String: kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly,
+        ]
+        let status = SecItemUpdate(query(account) as CFDictionary, attributes as CFDictionary)
+        if status == errSecItemNotFound {
+            let item = query(account).merging(attributes) { _, new in new }
+            SecItemAdd(item as CFDictionary, nil)
+        }
+    }
+
+    private static func delete(_ account: String) {
+        SecItemDelete(query(account) as CFDictionary)
+    }
+}