fix: support cancellation of conditional passkey autofill

[elpete]

Conditional passkey autofill can remain pending after a single-page application removes its login form. Add an optional third AbortSignal argument to autocomplete(redirectLocation, additionalParams, signal) so consumers can cancel on unmount or before another sign-in method starts.

The signal reaches both HTTP requests and the WebAuthn ceremony. Cancellation checks between stages prevent subsequent submission or redirect even when an asynchronous operation finishes after cancellation. Existing calls without a signal preserve their defaults, additional parameters, payload, and redirect behavior. Applications own the controller; cancellation cannot undo authentication already processed by the server.

Update the usage documentation and regenerate the shipped browser bundle.

Validation: all 10 JavaScript tests pass, including legacy invocation compatibility, cancellation at each asynchronous stage, and propagation through the shipped bundle to navigator.credentials.get. The CommandBox dependency packaging task and git diff --check pass. TestBox, hosted CI, and actual password-manager extension behavior were not verified for this JavaScript-only change.

Formatter workflow repair: pin CFFormat to 0.21.0 and run format:check without committing changes. CFFormat 0.22.1 repeatedly added whitespace before struct-key colons, and formatter commits triggered further workflow runs. Remove the accumulated formatting churn. Local validation confirms two clean checks, no changes on a second formatting pass, and exit status 1 for an unformatted glob fixture.