Support secure dialog input on the Parallels macOS 26/27 lanes

[malpern]

Granting Accessibility or Input Monitoring on macOS 27 raises an authenticated password prompt. secure-dialog-input refused every lane but Tart macOS 15, so the denied-to-allowed transition could not be automated at all on the lanes KeyPath and Typover actually test — including every "newly granted" row in docs/testing/macos-27-regression.md.

Why the Tart path could not be reused

It requires peekaboo and mcporter under /opt/homebrew inside the guest, and the Parallels desktop base has no Homebrew at all.

So this delivers the credential with the key-event transport secure_console_submit already proves out, which needs nothing installed in the guest. The plaintext is still read only from an owner-only temp file and never enters argv, logs, the guest pasteboard, or an artifact, and the accepted alphabet stays exactly as narrow.

Delivery is not success

The sheet-closed postcondition is preserved, matching the Tart lane — without it, a credential that never reached the field reports a pass. It runs through the peekaboo the base installs at a stable path.

Verified that the assertion bites: defeating the postcondition makes the suite fail with authentication sheet did not close, and the command reports passed when it should not.

Live verification on macOS 27

Not just unit-tested. On a real lease, driving Typover's first-run permission flow:

secure_dialog_input      passed
credential_transport     parallels-key-events

Then confirmed independently rather than trusting the exit status:

• the Accessibility toggle for Typover switched on in System Settings
• after relaunch Typover reports Accessibility, Allowed
• Input Monitoring still reports Not yet allowed, so the grant was specific rather than a blanket change

Note for whoever automates these flows next

peekaboo click did not reliably invoke Typover's SwiftUI button — it timed out while the sheet stayed closed. peekaboo perform-action --action AXPress worked first try. That matches what p01-unmanaged-input-monitoring-spike.md already recorded for KeyPath's wizard controls, so it is now two projects with the same finding: prefer perform-action over click for SwiftUI targets.

🤖 Generated with Claude Code

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[malpern]

Superseded by #1259.

The Parallels macOS 26/27 secure dialog input from this PR was ported into the vm-lab repository (commit f0ca542) along with its tests, and the sheet-closed postcondition was re-verified to fail when defeated. #1259 deletes the Scripts/lab/remote.sh this PR modifies, so merging this afterwards would resurrect a deleted file.

No work is lost — the behaviour now lives where the lab does.