The niri IPC worker slept 1ms per event and never reconnected. Under an
event burst the per-event cap back-pressures the socket, niri fills its
send buffer and drops the stream; read_line then returns false, the
detached thread exits and the module freezes permanently.
Remove the per-event sleep so events drain as fast as they arrive, and
wrap the socket setup and read loop in a reconnect loop that backs off
and re-establishes the stream on drop. A running_ flag lets the thread
exit cleanly on teardown.
Fixes#5117.
Adds a per-workspace app-icon taskbar (Workspace class) to the
niri/workspaces module. Rebased onto master: integrated with the
existing window-rewrite feature so the {windows} and {total} format
replacements continue to work alongside the new taskbar.
Adds format-window-separator, window-rewrite and window-rewrite-default
options plus the {windows} format replacement to the niri/workspaces
module (rebased onto master; coexists with ignore-workspaces).