fix(tvos): skip SpringBoard system-modal probe on tvOS (#1351)

tvOS has no SpringBoard (it uses PineBoard/HeadBoard), so probing
com.apple.springboard for blocking system modals raises an XCTest failure
("Application com.apple.springboard is not running") that safely() cannot
trap, terminating the whole runner test. Every snapshot and alert
resolution then failed, and the CLI misreported it as the screen
"overwhelming the accessibility capture".

resolveBlockingSystemModal — the single chokepoint every snapshot/alert
path funnels through — assumed a SpringBoard host always exists. Model that
assumption explicitly with `hasSpringBoardSystemModalHost` and bail to
`.absent` when no host exists, so app-owned alert queries still run. The
fourth probe site (shouldRouteToSpringboardBlockingSystemModal) is already
`#if os(iOS)` and needs no change.

Add tvOS regression tests covering the snapshot and alert-resolution paths.

Author: thymikee

apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerTests+BlockingSystemModalResolution.swift

@@ -16,6 +16,10 @@ extension RunnerTests {
   func resolveBlockingSystemModal(
     deadline: Date
   ) -> BlockingSystemModalResolution {
+    guard Self.hasSpringBoardSystemModalHost else {
+      return .absent
+    }
+
     guard let springboardModal = firstBlockingSystemModal(
       in: springboard,
       deadline: deadline
@@ -90,5 +94,20 @@ extension RunnerTests {
     XCTAssertFalse(RemoteHostedSystemModalPolicy.isEligibleHostState(.notRunning))
     XCTAssertFalse(RemoteHostedSystemModalPolicy.isEligibleHostState(.unknown))
   }
+
+  // tvOS has no SpringBoard host, so both the snapshot and alert-resolution paths
+  // must resolve without probing com.apple.springboard (#1351).
+  #if os(tvOS)
+  func testResolveBlockingSystemModalIsAbsentWithoutSpringBoardOnTvOS() {
+    guard case .absent = resolveBlockingSystemModal(deadline: .distantFuture) else {
+      XCTFail("tvOS blocking system-modal resolution must be .absent")
+      return
+    }
+  }
+
+  func testBlockingSystemAlertSnapshotIsNilOnTvOS() {
+    XCTAssertNil(blockingSystemAlertSnapshot(deadline: .distantFuture))
+  }
+  #endif
 }
 #endif

apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerTests.swift

@@ -29,6 +29,15 @@ final class RunnerTests: XCTestCase {
   }
 
   static let springboardBundleId = "com.apple.springboard"
+  // SpringBoard hosts blocking system modals on iOS/visionOS; tvOS (PineBoard/HeadBoard)
+  // and macOS have no such host, so there is nothing to probe there.
+  static let hasSpringBoardSystemModalHost: Bool = {
+    #if os(tvOS) || os(macOS)
+      return false
+    #else
+      return true
+    #endif
+  }()
   static let defaultRecordingFps: Int32 = 15
   var listener: NWListener?
   var doneExpectation: XCTestExpectation?