Add UI to configure Spotify Client ID in Settings

- Add expandable Configuration section in Spotify settings
- Store Client ID in UserDefaults
- Show Connect button only when Client ID is configured
- Add helper text pointing to Spotify Developer Dashboard

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

IrisCompanion/iris/Spotify/SpotifyAuthManager.swift

@@ -11,7 +11,6 @@ import Foundation
 import os
 
 enum SpotifyConfig {
-    static let clientId = "YOUR_SPOTIFY_CLIENT_ID"
     static let redirectUri = "iris-spotify-auth://callback"
     static let scopes = "user-read-playback-state user-read-currently-playing"
     static let authUrl = "https://accounts.spotify.com/authorize"
@@ -24,17 +23,31 @@ final class SpotifyAuthManager: NSObject, ObservableObject {
     @Published private(set) var isConnected: Bool = false
     @Published private(set) var isAuthenticating: Bool = false
     @Published private(set) var error: String? = nil
+    @Published private(set) var clientId: String = ""
 
     private let logger = Logger(subsystem: Bundle.main.bundleIdentifier ?? "iris", category: "SpotifyAuth")
     private let tokensKey = "spotify_tokens"
+    private let clientIdKey = "spotify_client_id"
     private var codeVerifier: String? = nil
     private var authSession: ASWebAuthenticationSession? = nil
 
+    var isConfigured: Bool {
+        !clientId.isEmpty
+    }
+
     override init() {
         super.init()
+        clientId = UserDefaults.standard.string(forKey: clientIdKey) ?? ""
         loadTokens()
     }
 
+    func setClientId(_ id: String) {
+        let trimmed = id.trimmingCharacters(in: .whitespacesAndNewlines)
+        clientId = trimmed
+        UserDefaults.standard.set(trimmed, forKey: clientIdKey)
+        logger.info("Spotify Client ID updated")
+    }
+
     var accessToken: String? {
         loadStoredTokens()?.accessToken
     }
@@ -50,7 +63,7 @@ final class SpotifyAuthManager: NSObject, ObservableObject {
 
         var components = URLComponents(string: SpotifyConfig.authUrl)!
         components.queryItems = [
-            URLQueryItem(name: "client_id", value: SpotifyConfig.clientId),
+            URLQueryItem(name: "client_id", value: clientId),
             URLQueryItem(name: "response_type", value: "code"),
             URLQueryItem(name: "redirect_uri", value: SpotifyConfig.redirectUri),
             URLQueryItem(name: "scope", value: SpotifyConfig.scopes),
@@ -145,7 +158,7 @@ final class SpotifyAuthManager: NSObject, ObservableObject {
             "grant_type": "authorization_code",
             "code": code,
             "redirect_uri": SpotifyConfig.redirectUri,
-            "client_id": SpotifyConfig.clientId,
+            "client_id": clientId,
             "code_verifier": verifier
         ]
 
@@ -172,7 +185,7 @@ final class SpotifyAuthManager: NSObject, ObservableObject {
         let body = [
             "grant_type": "refresh_token",
             "refresh_token": refreshToken,
-            "client_id": SpotifyConfig.clientId
+            "client_id": clientId
         ]
 
         do {