Initial implementation of AccountSettings. (#6275)

* Make the UserPreference macro also generate an accessor for the key name.

* Initial implementation of AccountSettings.

- Add an AccountUserDefaults storage with a userID prefix on the key.
- Migrate the 2 values reset by AppSettings.resetSessionSpecificSettings to AccountSettings.

* Rename UserSettings.volatile() to UserSettings.mock()

Given it now has a userID parameter with a default value..

Components/BuildExtensions/Sources/Macros/UserPreference.swift

@@ -16,7 +16,7 @@
 /// persisted under a legacy key).
 ///
 /// A `reset<Name>()` method is also generated, which clears the stored value so it reverts to the
-/// default.
+/// default. Non-volatile preferences also get a `<name>Key` property exposing the storage key.
 @attached(accessor)
 @attached(peer, names: arbitrary)
 public macro UserPreference<Value>(key: String? = nil, defaultValue: Value, volatile: Bool = false) =
@@ -27,3 +27,13 @@ public macro UserPreference<Value>(key: String? = nil, defaultValue: Value, vola
 @attached(peer, names: arbitrary)
 public macro UserPreference(key: String? = nil, volatile: Bool = false) =
     #externalMacro(module: "MacrosImplementation", type: "UserPreferenceMacro")
+
+/// The storage key of a `@UserPreference`, distinct from `String` so that only a generated
+/// `<name>Key` property can be passed where a preference key is expected.
+public struct UserPreferenceKey: Sendable {
+    public let rawValue: String
+    
+    public init(_ rawValue: String) {
+        self.rawValue = rawValue
+    }
+}

Components/BuildExtensions/Sources/MacrosImplementation/UserPreferenceMacro.swift

@@ -45,6 +45,10 @@ enum UserPreferenceMacro {
             "_\(raw: name)VolatileValue"
         }
         
+        var keyPropertyName: TokenSyntax {
+            "\(raw: name)Key"
+        }
+        
         var resetMethodName: TokenSyntax {
             "reset\(raw: name.prefix(1).uppercased() + name.dropFirst())"
         }
@@ -157,6 +161,14 @@ extension UserPreferenceMacro: PeerMacro {
         }
         """)
         
+        if !preference.isVolatile {
+            peers.append("""
+            var \(preference.keyPropertyName): UserPreferenceKey {
+                .init(\(preference.key))
+            }
+            """)
+        }
+        
         peers.append(resetMethod(for: preference))
         
         return peers

Components/BuildExtensions/Tests/MacrosTests/UserPreferenceMacroTests.swift

@@ -5,7 +5,7 @@
 // Please see LICENSE files in the repository root for full details.
 //
 
-import MacrosImplementation
+@testable import MacrosImplementation
 import SwiftSyntaxMacrosTestSupport
 import XCTest
 
@@ -35,6 +35,10 @@ final class UserPreferenceMacroTests: XCTestCase {
                                  _hasSeenNewSoundBannerSubject.prepend(hasSeenNewSoundBanner).eraseToAnyPublisher()
                              }
                              
+                             var hasSeenNewSoundBannerKey: UserPreferenceKey {
+                                 .init("hasSeenNewSoundBanner")
+                             }
+                             
                              func resetHasSeenNewSoundBanner() {
                                  store.removeObject(forKey: "hasSeenNewSoundBanner")
                              }
@@ -65,6 +69,10 @@ final class UserPreferenceMacroTests: XCTestCase {
                                  _liveLocationSharingSessionsByRoomIDSubject.prepend(liveLocationSharingSessionsByRoomID).eraseToAnyPublisher()
                              }
                              
+                             var liveLocationSharingSessionsByRoomIDKey: UserPreferenceKey {
+                                 .init("liveLocationSharingTimeoutDatesByRoomID")
+                             }
+                             
                              func resetLiveLocationSharingSessionsByRoomID() {
                                  store.removeObject(forKey: "liveLocationSharingTimeoutDatesByRoomID")
                              }
@@ -95,6 +103,10 @@ final class UserPreferenceMacroTests: XCTestCase {
                                  _pusherProfileTagSubject.prepend(pusherProfileTag).eraseToAnyPublisher()
                              }
                              
+                             var pusherProfileTagKey: UserPreferenceKey {
+                                 .init("pusherProfileTag")
+                             }
+                             
                              func resetPusherProfileTag() {
                                  store.removeObject(forKey: "pusherProfileTag")
                              }
@@ -125,6 +137,10 @@ final class UserPreferenceMacroTests: XCTestCase {
                                  _viewSourceEnabledSubject.prepend(viewSourceEnabled).eraseToAnyPublisher()
                              }
                              
+                             var viewSourceEnabledKey: UserPreferenceKey {
+                                 .init("viewSourceEnabled")
+                             }
+                             
                              func resetViewSourceEnabled() {
                                  store.removeObject(forKey: "viewSourceEnabled")
                              }