Use macOS hostname for device name

TFM/App/TermindApp.swift

@@ -1,5 +1,4 @@
 import AgentKitScrubber
-import DeviceKit
 import SwiftData
 import SwiftUI
 import TermindApplication
@@ -159,7 +158,7 @@ struct TermindApp: App {
     }
 
     fileprivate static var computerName: String {
-        Device.current.safeDescription
+        MacDeviceName.current
     }
 
     #if canImport(AppKit)

TFM/Platform/MacDeviceName.swift

@@ -0,0 +1,30 @@
+import Darwin
+import DeviceKit
+import Foundation
+
+enum MacDeviceName {
+    static var current: String {
+        resolved(kernelHostname: kernelHostname(), fallback: Device.current.safeDescription)
+    }
+
+    static func resolved(kernelHostname: String?, fallback: String) -> String {
+        guard let kernelHostname else { return fallback }
+        let hostname = kernelHostname.trimmingCharacters(in: .whitespacesAndNewlines)
+        return hostname.isEmpty ? fallback : hostname
+    }
+
+    static func kernelHostname() -> String? {
+        var size = 0
+        guard sysctlbyname("kern.hostname", nil, &size, nil, 0) == 0, size > 0 else {
+            return nil
+        }
+
+        var buffer = [CChar](repeating: 0, count: size)
+        guard sysctlbyname("kern.hostname", &buffer, &size, nil, 0) == 0 else {
+            return nil
+        }
+
+        let utf8 = buffer.prefix { $0 != 0 }.map { UInt8(bitPattern: $0) }
+        return String(decoding: utf8, as: UTF8.self)
+    }
+}

TFMTests/MacDeviceNameTests.swift

@@ -0,0 +1,31 @@
+import Foundation
+import Testing
+
+@testable import Termind
+
+struct MacDeviceNameTests {
+    @Test
+    func kernelHostnameTakesPriorityOverFallback() {
+        let hostname = UUID().uuidString
+        #expect(
+            MacDeviceName.resolved(
+                kernelHostname: hostname,
+                fallback: "fallback"
+            ) == hostname
+        )
+    }
+
+    @Test
+    func unavailableOrEmptyKernelHostnameUsesFallback() {
+        let fallback = UUID().uuidString
+        #expect(MacDeviceName.resolved(kernelHostname: nil, fallback: fallback) == fallback)
+        #expect(MacDeviceName.resolved(kernelHostname: "", fallback: fallback) == fallback)
+        #expect(MacDeviceName.resolved(kernelHostname: " \n ", fallback: fallback) == fallback)
+    }
+
+    @Test
+    func kernelHostnameIsReadable() throws {
+        let hostname = try #require(MacDeviceName.kernelHostname())
+        #expect(!hostname.isEmpty)
+    }
+}