fix: resolve SystemExtensionManager deadlock and state persistence issues

- Fix health check timer deadlock by running timer on global queue instead of same queue as performHealthCheck()
- Switch SystemExtension DeviceClaimer from systemDomainMask to userDomainMask for proper permissions
- Implement state persistence in CLI SystemExtensionManager stub to track claimed devices between commands
- Add proper error logging for state directory creation failures

Fixes issue where unbind command reported "Device was not claimed by System Extension" due to missing state persistence.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: beriberikix

Sources/SystemExtension/IOKit/DeviceClaimer.swift

@@ -83,7 +83,7 @@ public class IOKitDeviceClaimer: DeviceClaimer {
             category: "device-claimer"
         )
 
-        let stateDir = FileManager.default.urls(for: .applicationSupportDirectory, in: .systemDomainMask)
+        let stateDir = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
             .first?.appendingPathComponent("usbipd-mac")
         let statePath = stateDir?.appendingPathComponent("claimed-devices.json").path ?? "/tmp/usbipd-claimed-devices.json"
 
@@ -111,11 +111,19 @@ public class IOKitDeviceClaimer: DeviceClaimer {
 
         // Create state directory if needed
         let stateDir = (stateFilePath as NSString).deletingLastPathComponent
-        try? FileManager.default.createDirectory(
-            atPath: stateDir,
-            withIntermediateDirectories: true,
-            attributes: nil
-        )
+        do {
+            try FileManager.default.createDirectory(
+                atPath: stateDir,
+                withIntermediateDirectories: true,
+                attributes: nil
+            )
+            logger.debug("Created state directory", context: ["stateDir": stateDir])
+        } catch {
+            logger.warning("Failed to create state directory", context: [
+                "stateDir": stateDir,
+                "error": error.localizedDescription
+            ])
+        }
 
         logger.info("IOKitDeviceClaimer initialized", context: [
             "stateFilePath": stateFilePath,

Sources/USBIPDCore/SystemExtension/SystemExtensionManager.swift

@@ -401,7 +401,7 @@ public class SystemExtensionManager {
     private func startHealthCheckTimer() {
         guard config.healthCheckInterval > 0 else { return }
 
-        healthCheckTimer = DispatchSource.makeTimerSource(queue: queue)
+        healthCheckTimer = DispatchSource.makeTimerSource(queue: DispatchQueue.global())
         healthCheckTimer?.schedule(
             deadline: .now() + .seconds(Int(config.healthCheckInterval)),
             repeating: .seconds(Int(config.healthCheckInterval))

Sources/USBIPDCore/SystemExtension/SystemExtensionStubs.swift

@@ -19,8 +19,25 @@ public protocol DeviceClaimer {
 /// Stub implementation of IOKit-based device claiming
 public class IOKitDeviceClaimer: DeviceClaimer {
     private var claimedDevices: [ClaimedDevice] = []
+    private let stateFilePath: String
 
-    public init() {}
+    public init() {
+        // Use user Application Support directory for state persistence
+        let stateDir = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
+            .first?.appendingPathComponent("usbipd-mac")
+        self.stateFilePath = stateDir?.appendingPathComponent("cli-claimed-devices.json").path ?? "/tmp/usbipd-cli-claimed-devices.json"
+        
+        // Create state directory if needed
+        let stateDirPath = (stateFilePath as NSString).deletingLastPathComponent
+        try? FileManager.default.createDirectory(
+            atPath: stateDirPath,
+            withIntermediateDirectories: true,
+            attributes: nil
+        )
+        
+        // Restore state on initialization
+        try? restoreClaimedDevices()
+    }
 
     public func claimDevice(device: USBDevice) throws -> ClaimedDevice {
         let deviceID = "\(device.busID)-\(device.deviceID)"
@@ -43,12 +60,14 @@ public class IOKitDeviceClaimer: DeviceClaimer {
         )
 
         claimedDevices.append(claimedDevice)
+        try saveClaimState()
         return claimedDevice
     }
 
     public func releaseDevice(device: USBDevice) throws {
         let deviceID = "\(device.busID)-\(device.deviceID)"
         claimedDevices.removeAll { $0.deviceID == deviceID }
+        try saveClaimState()
     }
 
     public func getAllClaimedDevices() -> [ClaimedDevice] {
@@ -60,11 +79,28 @@ public class IOKitDeviceClaimer: DeviceClaimer {
     }
 
     public func saveClaimState() throws {
-        // Stub implementation - would save to persistent storage
+        do {
+            let data = try JSONEncoder().encode(claimedDevices)
+            try data.write(to: URL(fileURLWithPath: stateFilePath))
+        } catch {
+            // Don't fail the operation, just log the error
+            print("Warning: Failed to save device claim state: \(error.localizedDescription)")
+        }
     }
 
     public func restoreClaimedDevices() throws {
-        // Stub implementation - would restore from persistent storage
+        guard FileManager.default.fileExists(atPath: stateFilePath) else {
+            return // No state file, start with empty list
+        }
+        
+        do {
+            let data = try Data(contentsOf: URL(fileURLWithPath: stateFilePath))
+            claimedDevices = try JSONDecoder().decode([ClaimedDevice].self, from: data)
+        } catch {
+            // Don't fail the operation, just log the error
+            print("Warning: Failed to restore device claim state: \(error.localizedDescription)")
+            claimedDevices = []
+        }
     }
 }