Fix 7 pre-existing test failures in isolated HOME environment

[malpern]

Summary

7 tests consistently fail when run via Scripts/run-tests-safe.sh because the script sets HOME to a temp directory for isolation, but these tests expect real system plist paths or launchctl state.

Failing Tests

• PrivilegedOperationsCoordinatorTests.testRegenerateServiceConfigurationAllowsPendingApprovalPostcondition
• PrivilegedOperationsCoordinatorTests.testRestartUnhealthyServicesFailsWhenPostconditionTimesOut
• ServiceBootstrapperTests.testLoadServicesInTestModeReturnsFalseWhenAnyPlistMissing
• ServiceBootstrapperTests.testRepairVHIDDaemonServicesInTestModeSetsOutput
• ServiceBootstrapperTests.testUnloadAndInstallPathsReturnSuccessInTestMode
• ServiceHealthCheckerTests.testCheckKanataServiceHealthDoesNotProbeSystemInTestMode
• ServiceHealthCheckerTests.testIsServiceLoadedUsesPlistExistenceInTestMode

Root Cause

run-tests-safe.sh sets HOME to a temp directory to prevent parallel-agent collisions and keep tests hermetic. These tests rely on system paths derived from HOME (e.g., ~/Library/LaunchDaemons/) which don't exist in the temp directory.

Proposed Fix

• Add test-mode path remapping or mock the plist existence checks
• Ensure TestEnvironment.isRunningTests guards are in place for system-dependent operations
• Alternatively, create required directory structure in the temp HOME during test setUp

Context

Discovered while fixing CI for PR #217 (Karabiner converter). These failures are pre-existing on master and unrelated to that feature.