feat(grilling): omp-aware interview redesign, absorb ask-etiquette law

Rewritten per grilling-on-grilling (2026-10-18, all branches settled via
ask rounds): ask tool is the default round vehicle (one artefact per
question, recommended:0 = bare-yes semantics, hybrid boundary ask-default
/ prose-exception); todo as visible decision tree (phase=branch, blocked
reasons) + durable local://grilling-state.md ledger surviving the
Esc-aborts-the-run path; scout=environment facts (spawn-before-ask,
exclusive concurrency), web_search=world facts, inline=cheap lookups;
completion gate = summary + one closing ask, then distilled decisions
land in omp-docs/log.md via branch -> PR.

Absorbs managed skill one-decision-per-ask-question (Frank's choice;
reworded: ideas heavily encouraged via own atomic question, ban is on
smuggling into option text only). Managed skill deleted here; heartbeat
drops it from the live tree.

agent/managed-skills/one-decision-per-ask-question/SKILL.md

@@ -1,27 +0,0 @@
----
-name: one-decision-per-ask-question
-description: "Use when putting decisions to Frank via the ask tool or a grilling round — exactly one work item per question, rounds may group many single-item questions."
----
-
-# One Decision, One Work Item, One Question
-
-Friction-earned rule (corrected twice on 2026-10-18, during the voice/TTS planning).
-
-## Rules
-
-- Each question addresses **exactly one work item**. A round may contain many questions covering different work items; a question may not.
-- Never merge two artefacts into one option because they share an implementation dependency. Sharing an endpoint, a service, or a build step is NOT grounds for one question. (`frank-tts` serving both a podcast and an audiobook generator produced exactly this bug.)
-- Never offer something Frank did not ask for inside another question's option text. If an idea is mine, it gets its own question or stays out of the plan; it never rides along as "…and also X" in an option label or preview.
-- Do not derive option wording from my own scaffolding (todo text, my table row labels, my runbook headings). Derive it from his stated goal.
-- Mark the recommended option; a bare "yes" must accept it.
-- Facts are mine to fetch (subagent/scout), never a question for him. Only decisions go to him.
-- A question whose answer depends on an unsettled fact or another open question belongs to a **later round**, not this one.
-
-## Anti-patterns that triggered this
-
-- One option: "Audiobook/podcast factory — open-notebook + EPUB→narration builder." Two products, one shared dependency, zero requests for the second one. He answered "I never asked for audiobook generation."
-- One question: "Is the deliverable the podcast, or the platform (harness voice + OpenWebUI + alerts)?" Four work items in one question. Rejected: "You're lumping multiple asks into one question. Ask me per item."
-
-## Check before sending
-
-For each question: can I name the single artefact it decides? If two names come to mind, split it.