fix(desktop): resolve Swift concurrency error in release build

- Fix 'reference to captured var in concurrently-executing code' error
  by creating immutable copy of session before MainActor.run
- Exclude Info.plist and entitlements from SPM target to remove warnings

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

Author: grokify

apps/desktop/Package.swift

@@ -23,6 +23,10 @@ let package = Package(
                 .product(name: "AssistantKit", package: "assistantkit-swift")
             ],
             path: "Sources/PlexusOneDesktop",
+            exclude: [
+                "Info.plist",
+                "PlexusOneDesktop.entitlements"
+            ],
             resources: [
                 .copy("Resources/AppIcon.icns")
             ]

apps/desktop/Sources/PlexusOneDesktop/Views/NewSessionSheet.swift

@@ -112,9 +112,10 @@ struct NewSessionSheet: View {
             do {
                 var session = try await sessionManager.createSession(name: sessionName, command: command)
                 session.agentType = selectedAgentType
+                let createdSession = session  // Immutable copy for concurrent access
 
                 await MainActor.run {
-                    onSessionCreated(session)
+                    onSessionCreated(createdSession)
                     dismiss()
                 }
             } catch {