fix: StoreKit config path and Swift 6 concurrency warnings

The StoreKitConfigurationFileReference added in #11 used one '../' too
many, resolving outside the repository. Xcode resolves it relative to
the .xcodeproj's xcshareddata directory, so two levels reaches the repo
root.

SweepActivityAttributes is now explicitly nonisolated. The app target
sets SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor while the widget target
does not, so a type shared by both inferred a main-actor-isolated
ActivityAttributes conformance that ActivityKit cannot use from its
concurrent contexts.

LocalAPIService's logger closures captured self strongly while their
inner Tasks declared [weak self]. The weak capture is now on the outer
closure and bound before the Task, so the concurrently-executing closure
references an immutable strong local rather than the weak capture.

3 files changed, 14 insertions, 9 deletions

diff --git a/DomainDig.xcodeproj/xcshareddata/xcschemes/DomainDig.xcscheme b/DomainDig.xcodeproj/xcshareddata/xcschemes/DomainDig.xcscheme
index c51d109..c6b73a4 100644
--- a/DomainDig.xcodeproj/xcshareddata/xcschemes/DomainDig.xcscheme
+++ b/DomainDig.xcodeproj/xcshareddata/xcschemes/DomainDig.xcscheme
@@ -58,7 +58,7 @@
          </CommandLineArgument>
       </CommandLineArguments>
       <StoreKitConfigurationFileReference
-         identifier = "../../../DomainDig.storekit">
+         identifier = "../../DomainDig.storekit">
       </StoreKitConfigurationFileReference>
    </LaunchAction>
    <ProfileAction
diff --git a/LocalAPIService.swift b/LocalAPIService.swift
index ad1e07d..7d42128 100644
--- a/LocalAPIService.swift
+++ b/LocalAPIService.swift
@@ -182,14 +182,16 @@ final class LocalAPIService {
         let server = LocalAPIServer(
             port: Self.sanitizedPort(config.port),
             token: token,
-            requestLogger: { log in
-                Task { @MainActor [weak self] in
-                    self?.record(log)
+            requestLogger: { [weak self] log in
+                guard let self else { return }
+                Task { @MainActor in
+                    self.record(log)
                 }
             },
-            stateLogger: { stateMessage in
-                Task { @MainActor [weak self] in
-                    self?.statusMessage = stateMessage
+            stateLogger: { [weak self] stateMessage in
+                guard let self else { return }
+                Task { @MainActor in
+                    self.statusMessage = stateMessage
                 }
             }
         )
diff --git a/Shared/SweepActivityAttributes.swift b/Shared/SweepActivityAttributes.swift
index ee03c2d..81e7d02 100644
--- a/Shared/SweepActivityAttributes.swift
+++ b/Shared/SweepActivityAttributes.swift
@@ -4,8 +4,11 @@ import Foundation
 /// Live Activity contract for an in-flight watchlist sweep or batch lookup.
 ///
 /// Lives in `Shared/` because the app starts/updates the activity and the
-/// widget extension renders it.
-struct SweepActivityAttributes: ActivityAttributes {
+/// widget extension renders it. Explicitly `nonisolated`: the app target sets
+/// `SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor`, which would otherwise infer a
+/// main-actor-isolated `ActivityAttributes` conformance that ActivityKit cannot
+/// use from its concurrent contexts.
+nonisolated struct SweepActivityAttributes: ActivityAttributes {
     struct ContentState: Codable, Hashable {
         var completed: Int
         var total: Int