fix: pin desktop-tools with passing Peekaboo patch tests

[iamnbutler]

Pins desktop-tools to githubnext/desktop-tools#10 (20cb1b5), which makes every Peekaboo 4.8.0 patch-stack test pass again (#390).

• Each patch now carries the test updates for the behavior it intentionally changes: insert, quit, launch, point-focus, and stale-click.
• Two click-patch bugs are fixed in the code:
  • The click-focus write now goes through the element seam (focusAutomationElement). It used to bypass the element with a raw AX write, which hit the real process and made AsyncAXMutationTests fail and hang.
  • The tab-selection check runs inside the injected verifier again.
• The native build now restores a scratch Peekaboo checkout that matches no pinned patch prefix. For example, a checkout left by an earlier revision of a patch is restored before the stack is applied, so it no longer fails.
• bun.lock also picks up the stale apps/desktop version (0.0.41 to 0.0.46).

Two pre-existing upstream failures remain, and both also fail on unpatched 4.8.0:

• DesktopObservationServiceTests.testGenerationlessRemoteExactObservationStaysReadOnly, which depends on the host
• the PeekabooBridge zombie-reap test

Built in Ace

No — built with Claude Code outside Ace by an overnight issue watcher, because this Mac's Ace Canary is a participant in the running two-person study (#218); dogfooding gap tracked in #5.