Clear four compiler warnings in E2EInbox and TodayStore

Three @Published properties carried internal(set) on an internal
property, which changes nothing. forgetOnThisPhone defaulted its store
to .shared, evaluated outside the main actor; it now takes an optional
and resolves .shared inside the body.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Sources/E2E/E2EInbox.swift

@@ -542,13 +542,13 @@ final class E2EInbox: ObservableObject {
 
     /// Section 17.6 and 8.9d, see `E2EInbox+AccountState.swift`. Written only
     /// through `writeSync` and the merge of what linked devices send.
-    @Published internal(set) var syncState = SyncState()
+    @Published var syncState = SyncState()
     /// Section 17.3: the code this device is showing so a linked device can
     /// link it, and when it stops being good. Memory only: ten minutes, one
     /// use.
-    @Published internal(set) var pendingLinkCode: (code: DeviceLinkCode, expires: Date)?
+    @Published var pendingLinkCode: (code: DeviceLinkCode, expires: Date)?
     /// A numeric-fallback offer held until the person confirms the number here.
-    @Published internal(set) var pendingNumericOffer: PendingLinkOffer?
+    @Published var pendingNumericOffer: PendingLinkOffer?
     /// What the person is told about changes to the linked set.
     @Published var linkNotices: [LinkNotice] = []
     /// Section 17.6: ops written here, waiting to go to the linked devices.

Sources/Today/TodayStore.swift

@@ -393,8 +393,10 @@ final class TodayStore: ObservableObject {
     /// other traces. The file is public; the picks say where somebody cares
     /// about, and the next person to use this phone has no business with
     /// either.
-    static func forgetOnThisPhone(_ store: TodayStore = .shared, defaults: UserDefaults = .standard) {
-        store.forgetEverything()
+    /// `store` is optional because a default of `.shared` is evaluated
+    /// outside the main actor, which Swift 6 refuses.
+    static func forgetOnThisPhone(_ store: TodayStore? = nil, defaults: UserDefaults = .standard) {
+        (store ?? .shared).forgetEverything()
         defaults.removeObject(forKey: TodayPlaces.key)
     }
 }