Run refresh callbacks on the pump that sent them

evidence/refresh-callback-task-owner-20261006/README.md

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+# Refresh callback execution belongs to its sender
+
+Screen retained each callback with its sender, checked that sender's paint, then
+awaited the callback on Screen's task inside the sender's context. An async
+callback could wait for its sender's next refresh: wait_for_refresh saw a foreign
+task, queued another Screen callback, and waited while Screen was still awaiting
+the first callback. One async widget callback could also prevent unrelated
+senders' paint and callback admission.
+
+Screen now owns admission only. It hands each admitted callback to the sender's
+existing call_later / events.Callback / on_callback path. That original pump owns
+execution, self-wait refusal, errors and teardown. No new task or queue is added.
+Held callbacks remain in Screen's same queue; the original subtree, whole-frame,
+batch and backdrop checks remain. One synchronous drain borrows one preparation
+cohort; the repeated preparation and foreign callback context/invocation were
+deleted. No preparation is acquired for an empty or batched callback queue.
+
+Existing Package parser covered 249 native production modules, 463 native tests
+and 288 Toad dependency modules with zero omissions. before.json records 208
+lexical declaration/consumer sites. External dynamic callback targets remain
+unresolved. Toad sources were read, not edited.
+
+This source defect is not established as physical04's cause. The original footage
+shows saved transcript paint. A callback held behind native readiness does not
+itself suppress the capture helper's independent asyncio timeout; its missing
+DTO/error still needs Parent's helper trace. Original recordings, helpers,
+wheels and failed capture remain unchanged.
+
+## Changed-path qualification
+
+`PYTHONPATH=src PYTHONDONTWRITEBYTECODE=1 /usr/bin/python -m pytest -q
+tests/test_refresh_callback_owner.py tests/test_lazy.py::test_lazy
+tests/test_reparent.py::test_reparent_preserves_order_and_transfers_pending_frame_callbacks
+--tb=short`: **5 passed in 0.79s**, terminal exit 0.
+
+The three new real run_async/HeadlessDriver cases confirm App/widget callbacks run
+on their own actual tasks, retain the original self-wait refusal and allow another
+sender's actual paint/callback while suspended. Held subtree, Screen and App
+callbacks remain queued until the original roots release. The two existing cases
+cover the directly affected async Lazy mount/self-removal and original queued
+callback transfer on reparent. No old native73/74 or physical check was repeated.
+
+after.json covers 249 native modules, 464 tests and the same 288 read-only Toad
+dependency modules, zero omissions. Screen's foreign invocation/context were
+deleted; original MessagePump.on_callback is now the shared execution consumer.
+
+No installed, terminal-writer, Toad physical or provider run occurred. Original
+writer hooks/receipts were not edited; actual matching Toad/terminal acceptance
+and the original missing capture response remain unqualified. All test App tasks
+returned; no process or runtime was left running.