v0.5.0

Added

• Overview of all files: with two or more files, an Overview entry tops the file drawer and shows every file's todos at once, grouped by file in the list, one board per file (with its own columns) and one merged calendar; actions write to the todo's own file, the add dialog lets you pick the file for a new todo, and drawer counts and project/context renames span every file

Fixed

• Dragging the title bar moves the window while a dialog is open; pressing it used to close the dialog instead