feat: add FileBookmarkService, BiometricAuthService, ClipboardService

Phase 3 (Tasks 10-11) app services: FileBookmarkService persists a
security-scoped bookmark for the KDBX file in the shared App Group;
BiometricAuthService wraps LAContext for Face ID/Touch ID; ClipboardService
copies text with an expiring clipboard entry on iOS/macOS.

Also fixes a real build issue found while verifying: the AutoFill
extension (iOS-only) was being embedded/signed unconditionally,
breaking macOS builds of the MyPass scheme with a bogus provisioning
error. Added platformFilters = (ios) to both the embed build file and
the target dependency so macOS builds skip it. Verified both iOS
Simulator and macOS builds now fail only on the known, expected
ContentView.swift/Item SwiftData breakage.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WYqycDFsynHH9VnnK7LNSf

MyPass/Services/ClipboardService.swift

@@ -0,0 +1,30 @@
+//
+//  ClipboardService.swift
+//  MyPass
+//
+
+import Foundation
+#if os(iOS)
+import UIKit
+#else
+import AppKit
+#endif
+
+public enum ClipboardService {
+    public static func copy(_ text: String, expiresAfter seconds: TimeInterval = 30) {
+        #if os(iOS)
+        UIPasteboard.general.setItems(
+            [[UIPasteboard.typeAutomatic: text]],
+            options: [.expirationDate: Date().addingTimeInterval(seconds)]
+        )
+        #else
+        let pb = NSPasteboard.general
+        pb.clearContents()
+        pb.setString(text, forType: .string)
+        let captured = text
+        DispatchQueue.main.asyncAfter(deadline: .now() + seconds) {
+            if pb.string(forType: .string) == captured { pb.clearContents() }
+        }
+        #endif
+    }
+}