Implements the deferred Windows primary-only CCD (Stage 2). set_virtual_primary_ccd
repositions the virtual output's source to (0,0) = primary and shifts the physical
display(s) to its right, ALL kept active — one atomic CCD SetDisplayConfig (not GDI
CDS_SET_PRIMARY, which storms MODE_CHANGE_IN_PROGRESS with another display live).
The manager's should_isolate() becomes topology_action() (3-way): extend (skip),
primary (set_virtual_primary_ccd), exclusive (isolate_displays_ccd). Restore-on-teardown
covers both. Validates the user's two scenarios on a physical-monitor .173.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
eda7cac78e