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/skills/grilling/SKILL.md

@@ -3,30 +3,40 @@ name: grilling
 description: Grill the user relentlessly about a plan, decision, or idea. Use when the user wants to stress-test their thinking, or uses any 'grill' trigger phrases.
 ---
 
-> **Authored override.** Extracted 2026-10-18 from `mattpocock/skills` (identical to upstream at extraction) into the command-center repo so Frank can customize it. Removed from the `skills` CLI global store (`~/.agents/.skill-lock.json` pruned) so `skills update -g` never resurrects a duplicate. Edits to this file are repo prose: branch → PR → Frank OK.
+> **Authored override.** Extracted 2026-10-18 from `mattpocock/skills` (identical to upstream at extraction) into the command-center repo so Frank can customize it. Removed from the `skills` CLI global store (`~/.agents/.skill-lock.json` pruned) so `skills update -g` never resurrects a duplicate. omp-aware redesign same day; absorbed the `one-decision-per-ask-question` managed skill. Edits to this file are repo prose: branch → PR → Frank OK.
 
 Interview the user relentlessly until you reach a shared understanding. Map this as a **design tree**: every decision branches into the decisions that hang off it.
 
-Work the tree in **rounds**. The **frontier** is every decision whose prerequisites are already settled: the questions you can ask _now_ without guessing at answers you haven't heard yet. Ask the whole frontier in one round: number each question and give your recommended answer. Then wait for the user's answers before the next round.
+Work the tree in **rounds**. The **frontier** is every decision whose prerequisites are already settled. A question whose answer depends on an unsettled fact or another open question belongs to a _later_ round, not this one. Ask the whole frontier in one round, then wait.
 
-Format a round like so:
+## The round: `ask` is the default vehicle
 
-```
-❓ **Q1** - **<question title>**: <question body, might be multiple paragraphs, including multiple choices>
+Every frontier decision that fits 2–5 options goes through the `ask` tool - one question per decision, `recommended: 0` (the recommended answer is always option 0; the user's single Enter is the bare "yes" that accepts it). Prose in chat is the exception, reserved for genuinely open narrative ("walk me through the deploy flow") - never as buttons.
 
-➡️ <your recommended answer>
+Per-question discipline (absorbed law, was the `one-decision-per-ask-question` managed skill):
 
----
+- One question decides exactly **one artefact**. Name it before sending; two names → split. A round may carry many single-artefact questions; a question may not.
+- Shared plumbing is not grounds for merging: two products sharing an endpoint, service, or build step are still two questions.
+- Ideas are **heavily encouraged** - the interviewer's own idea gets its own atomic question like any other. What is banned is smuggling an unasked-for artefact into another question's option text ("...and also X" in a label or preview).
+- Option wording derives from the user's stated goal, never from your scaffolding (todo text, table rows, runbook headings).
+- `multi: true` for pick-many; `preview` for code/config evidence (renders as markdown); `header` for the branch chip.
 
-❓ **Q2** - **<question title>**: <question body, might be multiple paragraphs, including multiple choices>
+Fallback: a harness without `ask` degrades to the classic text round - `❓ **Q1** - **title**: body` / `➡️ recommendation`, worded so a bare "yes" accepts every recommendation.
 
-➡️ <your recommended answer>
-```
+Dialog mechanics you must respect: `ask` is exclusive - spawn scouts **before** the `ask` call in the same message or they stall behind the dialog. The dialog cannot be interrupted by arriving facts; results land between rounds. Esc **aborts the whole run** with no post-cancel turn - the durable ledger is the safety net. Questions are spoken aloud when speech is enabled.
 
-Word each question so "yes" accepts your recommended answer.
+## The ledger: `todo` is the tree, `local://` is the save-file
 
-Each round the user answers reshapes the tree: settled decisions push the frontier outward and unblock questions that depended on them. Recompute the frontier and ask the next round. A question whose answer depends on another question still open in this round belongs to a _later_ round, not this one.
+- `todo`: **phase = design-tree branch**, task text = the decision (`"<decision> - via: <parent>"` carries the edge; todo has no edges). `pending` = frontier, `block` with a one-line reason = waiting on a fact or an open decision (the HUD stays visible while anything is blocked), `done` = settled. `unblock` the moment its prerequisite settles.
+- `write local://grilling-state.md` at the end of **every round**: the tree with each decision's verdict + one-line rationale. This is the only thing that survives an Esc-abort - keep it current.
 
-Finding _facts_ is your job, never the user's. When a frontier question needs a fact from the environment (filesystem, tools, etc.), dispatch a sub-agent to find it; don't ask the user for anything you could look up yourself. Don't block on it: a running exploration is an unsettled prerequisite, so only the questions downstream of it wait for the sub-agent to report; ask the rest of the frontier now. The _decisions_ are the user's: put each to them and wait.
+## Facts are yours; decisions are the user's
 
-The session is done when the frontier is empty: every branch of the design tree visited, nothing left silently assumed. Do not act on it until the user confirms you have reached a shared understanding.
+- Environment facts (filesystem, repo, live config): `task` + `scout`, one batch, one scout per fact-cluster; on this box at most 3 run at once, so cluster rather than spray.
+- Outside-world facts: call `web_search` directly - no spawn hop.
+- Cheap lookups: `read`/`grep` inline.
+- Only the main session may ask; every spawn carries the exact facts to return.
+
+## Completion
+
+Frontier empty and nothing blocked → write the settled-decisions summary from the ledger, then **one closing `ask`**: "Shared understanding reached - proceed?" Nothing executes before that yes. After it: distill the settled decisions into an `omp-docs/log.md` work-log entry through the normal branch → PR path, and refresh the ledger file to final form.