#5158 (6672e924) moved connectToSocket() off the constructing thread and
into the detached IPC worker's own try/catch, so a missing NIRI_SOCKET no
longer throws out of IPC::IPC(). That was needed to fix#5117 (the worker
should reconnect instead of dying when an established stream drops), but
it also meant the very first connection attempt can never fail anymore.
Factory::makeModule()/Bar::getModules() rely on that constructor throwing
to disable a module it can't construct. With niri/workspaces and
niri/window always constructing successfully now, they get added to every
bar regardless of which compositor is actually running, showing up as a
permanently-empty widget next to the real workspace modules under
Hyprland/Sway.
Restore the old semantics for the first connection: connectToSocket() runs
synchronously in IPC::IPC() again, so a missing socket still throws and
the module gets disabled as before. Only a drop *after* that succeeds
falls into the retrying reconnect loop, preserving the #5117 fix.
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.