fix: macOS 27 and Safari 27 live-check fixes, agent cursor order and outline on screen

[iamnbutler]

Fixed

• The agent cursor sits directly above the window the agent is using instead of above every window, so a window covering that app covers the cursor too. Input outside any one window, such as on the Dock or the menu bar, still shows it on top.
• The agent window outline and its label stay on the display when the window fills it; they were drawn just outside the window and ran off the screen's edges.
• desktop_close on a Finder window is completed again instead of unknown: Accessibility lists Finder's desktop as a window without an ID, which made every close unverifiable on macOS 27, even after the window was gone.
• desktop_wait and expect app conditions with bundle_id find the app when many apps are running; the app list cut to fit a result could drop it, and a cut list no longer counts as proof that an app quit.
• desktop_read with table: true finds the column titles of web tables in Safari 27, which reports <th> cells as plain cells.
• desktop_select in Safari 27 web text no longer crashes the Desktop Tools app, and finds text bounds without the text marker attributes Safari dropped.
• Pasting files with desktop_insert into a Finder window on macOS 27 finds the window's folder from its path bar, since Finder no longer reports it otherwise; without the path bar, the refusal says to turn on View > Show Path Bar.
• desktop_set_value on a Safari 27 date input is refused before input, with a hint to type the date, instead of unknown; it accepts an ISO 8601 date where a date can be set.
• Management failures, such as an unverified desktop_close, include the native cause, as action failures do.

Live checks on a dev build (macOS 27): 36/40 in the full run. #114 passes on rerun (an open Desktop Tools prompt blocked it), #77 Command-click is flaky (passed 2 of 2 reruns), and #120 failed only because its prompt went unanswered. New Peekaboo patches are appended to the stack; the close patch includes a policy test (WindowStateMutationPolicyTests passes).