The desktop showed rfd's synchronous dialogs on the UI thread, so the
window stopped answering the compositor while one was up: GNOME marked
LightCraft "not responding", the File menu stayed drawn and the control
channel went quiet. Services.picker lets the host start a dialog
elsewhere and answer through a channel; a command that needs a path
asks for one and returns, and runs again with the answer when the
dialog closes (pick.rs). Import Photos, Import from Folder, Open
Library, Import Lightroom Catalog, Find Missing Photos, the preset and
curve-preset imports and exports, Auto-Tag from Tracklog and Locate
Missing File use it; hosts without a picker (the web, tests) keep the
synchronous dialogs. ui.inspect lists the waiting commands as
fileDialogs. Same cause as storytold/photocraft#574.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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