fix(tasks): claim the teardown report before the producer cancel runs

A throwing producer cancel jumped to the force-fail branch before
`reported` was set, so `settle()` announced an unreported completion and
the default wakeup delivery started a model turn on an owner the host
was already destroying — the exact failure mode marking the record
reported exists to prevent.

Teardown claims the report before calling the producer, because that
decision does not depend on whether the producer's cancel succeeds.

Also reject a `maxConsecutiveWakes` that cannot bound anything: the
field exists to cap a runaway chain, and `Infinity` removed the cap
while a fraction never named a turn.

Correct the module JSDoc and the background-task runtime note, both of
which still promised that notices never wake an idle agent.

.agents/notes/implemented/architecture/2026-06-20-generic-long-running-tool-runtime.md

@@ -77,7 +77,7 @@ A producer loaded without any controller would let callers start work they canno
 
 Stream reads share one task-scoped consuming cursor because the owning model is the intended reader. A UI or multiple independent readers need a separate non-consuming observation API; sharing this cursor would let readers consume one another's output.
 
-The system prompt tells the model to retain task ids, continue independent work instead of busy-polling or duplicating a running task, collect relevant tasks before its final answer, and kill work that no longer matters. Completion injects a logged `context/message` into the exact owner's session; it becomes durable context for the next request but does not wake an idle agent.
+The system prompt tells the model to retain task ids, continue independent work instead of busy-polling or duplicating a running task, collect relevant tasks before its final answer, and kill work that no longer matters. Completion delivers a logged message to the exact owner's session. A busy owner is injected; an idle owner is woken, under the bounded policy the [idle-owner wake decision](../feature/2026-08-11-background-task-completion-wakes-an-idle-owner.md) owns.
 
 The runtime marks a terminal task `reported` when a read or wait delivers it, when a live waiter has claimed delivery at settlement, or when the model explicitly kills it. Reported tasks do not inject redundant completion notices. Listener failures are logged independently, do not stop later listeners, and are not awaited by waiters or teardown. When a snapshot carries `outputLimitBytes`, `dsh-tool-tasks` preserves UTF-8 boundaries and reuses an existing producer truncation marker rather than duplicating it. Reads reserve status suffixes and retain the output tail; completion notices reserve the stable `background task <id>` prefix and `task_output` instruction before truncating variable kind, label, status, detail, or the truncation marker itself, so the minimum PTY cap still identifies the task to collect. The task controller resolves the caller-visible producer cap in a prepended pre-execute listener before policy can deny or short-circuit dispatch, then applies it through the task definitions' last-mile `finalizeContent` callback so normalized tool errors, outer pipeline failures, and single-text policy results cannot escape the bound; deliberately structured multi-block policy results retain policy ownership of their shape and size.
 
@@ -131,4 +131,4 @@ Unit coverage pins preflight atomicity, per-kind ids, output-limit validation an
 
 Bash commands and subagents share one id vocabulary, listing, notice format, prompt habit, and set of control tools. New long-running producers implement execution hooks instead of another registry and tool family. The [tool cookbook](../../../../docs/cookbook/adding-a-tool.md) points producers to this contract.
 
-Owned background bash now stops with its agent instead of surviving it. Background processes have no executor timeout; callers must kill irrelevant work or rely on owner/service disposal. Stream reads support one consuming reader, completion notices do not wake idle agents, and a producer that returns from `cancel` without settling `done` can still stall teardown. Durable jobs, independent observation cursors, and foreground promotion remain separate designs.
+Owned background bash now stops with its agent instead of surviving it. Background processes have no executor timeout; callers must kill irrelevant work or rely on owner/service disposal. Stream reads support one consuming reader, and a producer that returns from `cancel` without settling `done` can still stall teardown. Durable jobs, independent observation cursors, and foreground promotion remain separate designs.