start({ kind, label, owner, run }) preflights everything that can fail
(the attachSurface fence, validation, the owner-cleanup attach) BEFORE
invoking the producer's run() starter, then commits atomically —
'work started but never got a collectable id' is now structurally
impossible instead of a producer try/catch rollback obligation (the
P1 review fix, rebuilt on #185's declare/execute split). Producers
lose their catch-wraps; the leak tests now pin the stronger property
that a failed preflight never spawns anything. TaskRegistration splits
into TaskStart (identity + run) and TaskHooks (cancel/done/readOutput);
docs, type-equiv manifest, catalogs, and both RFCs move with it.
ctx.tasks.wait arms a deadline() fusing the caller's abort with the
wait timeout and classifies the outcome with timeoutOf scoped to the
new TASK_WAIT_TIMEOUT code: a wait timeout resolves to the live
snapshot (the task keeps running), a caller abort rejects the wait —
same contract, no hand-rolled timer/listener plumbing, and a nested
foreign deadline can no longer misread as a wait timeout. task_output
deliberately declares NO ToolDefinition.timeoutMs: timeout-policy
turns a timed-out call into a structured TOOL_TIMEOUT failure, but a
timed-out wait is a SUCCESS that must still report [status: running]
(decision recorded in the runtime RFC alternatives).
One shared ctx.tasks registry (branded <kind>-N ids, owner-fenced
read/kill/wait/list, attachSurface misconfiguration fence, reported-flag
notice dedup, atomic register) + dsh-tool-tasks (task_output/task_list/
task_kill, completion-notice injection, background prompt habit).
Producers opt in via their own enableRunInBackground config: bash
(stream kind; seam slimmed to resolve/run/start returning a BashProcess
handle, bash_output/bash_kill deleted) and subagent (final-output kind;
done settles after run.dispose()). Owner disposal drains tasks through
the new awaited ctx.agents.onCleanup seam in the loop's disposal chain.
Both RFCs moved to implemented/; docs, catalogs, snapshots re-pinned.
