fix(ios): clear private native state and apply upstream dark tokens

Discard editor drafts on account/server changes, obscure inactive sheets and clear loaded records even when vault erasure fails. Serialize local removal and distinguish dark tint from primary button fill. Swift format/parsing and sixteen portable tests pass; Apple SDK validation remains outstanding.

ios/Sources/NativeStore.swift

@@ -175,26 +175,28 @@ final class NativeStore: ObservableObject {
                 revoked = true
             } catch { revoked = false }
             await api?.close()
+            clearLoadedData()
             try vault?.clear()
             if let address = try? ServerAddress(server), let storage = vault {
                 api = try NativeAPI(server: address, saved: nil, persist: storage.save)
             }
-            clearLoadedData()
             if !revoked { error = "Lokal abgemeldet. Die Abmeldung auf dem Server konnte nicht bestätigt werden." }
         }
     }
 
     func forget() async {
         guard !busy else { return }
+        busy = true
+        defer { busy = false }
         generation += 1
         await api?.close()
+        clearLoadedData()
         do { try vault?.clear() } catch {
             self.error = NativeAPIError.unavailable.errorDescription
             return
         }
         api = nil
         vault = nil
-        clearLoadedData()
         server = ""
         appName = "Yuvomi"
         setup = false