Carry the owning task's notification subscriptions independently of dependency
edges, within the creation transaction. Prefer its durable session over worker
and request-local sessions while preserving explicit overrides. Cover worker
CLI create and built-in decomposition, and retain conversation route anchors.
Auto-subscribe no longer upgrades an inherited passive subscription.
Slim adaptation of Christopher-Schulze's session-precedence fix in #85687,
expanded to durable subscription provenance and sibling creation paths.
Related: #85575, #85687
Validation: strict RED/GREEN (7 failing cases before; 7 passing after), then
58 Kanban test files: 383 passed, 2 skipped. Real dispatcher-spawn subprocess
probe covers direct, linked, unlinked, explicit-session, worker CLI, built-in
children and a plain CLI negative control, with recording transport only.
Co-authored-by: Christopher <210261288+Christopher-Schulze@users.noreply.github.com>
3b7ff435fd