reload: turn off incremental QML garbage collection

After a 33-minute suspend the desktop shell sat at ~45% of a core: its
main thread ran flat out for about a second every two seconds, in step
with the Perf 2s timer. Stack samples were almost all QV4 GC
(GCStateMachine::transition, MarkStack::drain) entered from allocData via
tryForceGCCompletion, under the regex loop in Perf.vram(), a 177-line
parse that should take microseconds. The main thread also posted ~1000
events a second to its own eventfd, against a few dozen in the other
shells. Reading: Qt 6.11's incremental collector, the default since 6.8,
never completed a cycle after resume, so every allocation forced a full
mark.

QV4_GC_TIMELIMIT=0 is Qt's documented switch back to non-incremental
collection. With it, after a 31-minute suspend the shell stayed at 0.3%
and ~37 wakeups a second. The live autostart.lua sets it too; keep the
two in step.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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