Add an explicit overlay unfocus target so callers can move input to the editor or another component while overlays remain visible. Align fallback overlay focus with visual focus order and cover blocked replacement release, null targets, and multi-overlay cycling.
Preserve a focused visible overlay as the input owner across extension custom UI replacement, while letting the replacement receive and close its own input before focus is restored. Fixes#5129.
detectCapabilities previously disabled hyperlinks under tmux unconditionally. tmux re-emits OSC 8 to the outer terminal only when the attached client advertises the 'hyperlinks' feature in client_termfeatures, and strips them otherwise.
Probe the running server with 'tmux display-message -p #{client_termfeatures}' and enable hyperlinks only when the feature is listed. The probe fails closed: any error (no tmux/server, timeout, old tmux) yields false. images stays null; only the hyperlink decision changed. The probe is injected into detectCapabilities so it stays testable without spawning a process.