orchestration: idle_timeout_secs accepted but silently inert, no runtime hint to the operator

[bug-ops]

Description

Spec-075 (#6243) ships idle_timeout_secs on TimeoutPolicy as a documented no-op in v1 — it is accepted in config/graph definitions but never enforced. Flagged by impl-critic (F7) during PR review, deliberately deferred to keep the PR scope focused.

Expected Behavior

If an operator sets idle_timeout_secs on a TaskNode or via default_idle_timeout_secs config, they should get some runtime signal (a one-time warning log, or a wizard/--init hint) that the value is currently inert, rather than silently accepting a config field that does nothing.

Actual Behavior

The field is accepted with no feedback that it is not yet enforced. The --init wizard help text and config comments do document "reserved — not yet enforced," but nothing fires at runtime when a user actually sets a value expecting timeout behavior.

Environment

• Version: main, post-PR closing Implement: orchestration node control parity (per-task run_timeout + Mode-1 recovery) #6243/orchestration: /plan confirm gives no user-visible signal when verification judges plan output incomplete #6265
• Crate: zeph-orchestration, zeph-config

Related

• Implement: orchestration node control parity (per-task run_timeout + Mode-1 recovery) #6243 (origin)