style(grilling): rewrite in the mattpocock corpus voice (Refs #20)

Read all 36 upstream skills, then rewrote to their house style per
writing-for-agents' own levers: leading words as tokens (frontier,
brief, ledger, artefact, scout), vocabulary-first and used exactly,
positive phrasing with prohibitions kept only as hard guardrails,
completion criteria sharpened to checkable+exhaustive ('counted before
sending', 'frontier empty and nothing sits blocked'), zero history,
gotchas the environment cannot confess kept inline. All settled
behaviour from the grilling-on-grilling session survives intact.

agent/skills/grilling/SKILL.md

@@ -3,36 +3,44 @@ 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.
 ---
 
-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.
+# Grilling
 
-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.
+Interview the user relentlessly until nothing is silently assumed. The subject is a **design tree**: every decision branches into the decisions that hang off it.
 
-## The round: `ask` is the default vehicle
+A decision is **frontier** when it can be asked now, without an answer you haven't heard yet. The interview is done when the frontier is empty: every branch of the tree visited.
 
-Per-question discipline:
+## Rounds
 
-- 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.
+Work the tree in **rounds**: ask the whole frontier at once, then wait. A decision whose answer hangs on an open question or an unfetched fact joins a later round.
 
-Fallback: a harness without `ask` degrades to the classic text round - `❓ **Q1** - **title**: body` / `➡️ recommendation`, worded so a bare "yes" accepts every recommendation.
+Ask each closed decision - anything expressible as 2–5 options - through the `ask` tool:
 
-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.
+- **One artefact per question**, counted before sending. Name the artefact each question decides; two names means two questions. Shared plumbing (an endpoint, a service, a build step) still leaves two artefacts.
+- Recommended answer first, marked `recommended: 0`: the user's single Enter accepts it.
+- Options quote the user's goal. Their words, their stated goal, ground the wording; your todo text and table rows stay out of it.
+- Your own idea is welcome: it gets its own recommended question. Attach it to its own question, so it rides there on its merits.
+- `multi: true` for pick-many, `header` for the branch chip, `preview` when the decision needs code or config in front of the user.
 
-## The ledger: `todo` is the tree, `local://` is the save-file
+Open narrative - "walk me through the deploy flow" - has no options to offer; ask it as prose in chat. Without an `ask` tool the whole round degrades to text: `❓ **Q1 — title**: body`, then `➡️ recommendation`, phrased so one bare "yes" accepts every recommendation.
 
-- `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.
+Dialog mechanics, the gotchas no doc confesses: the dialog is exclusive, so dispatch scouts before the `ask` call in the same message and expect their results between rounds. Esc cancels the whole run with no closing turn; the ledger below is what survives it.
 
-## Facts are yours; decisions are the user's
+## The ledger
 
-- Environment facts (filesystem, repo, live config): `task` + `scout`, one batch, one scout per fact-cluster; concurrency is capped, so cluster rather than spray.
-- Outside-world facts: call `web_search` directly - no spawn hop.
+The tree lives in the `todo` list while the interview runs, so the user watches it fall:
+
+- One task per decision, filed under the phase for its branch; `via: <parent decision>` in the task text carries the edge.
+- `pending` is the frontier; `block` with a one-line reason waits on a fact or an open decision; `done` is settled. Unblock the moment the dependency settles.
+
+Write `local://grilling-state.md` at the end of every round: the tree, each decision's verdict and one-line rationale. It is the durable copy of the interview; keep it current so an Esc costs one round.
+
+## Facts are yours, decisions are theirs
+
+- Environment facts (filesystem, repo, live config): dispatch a **scout** per fact-cluster, batched into one `task` call, before the round's `ask`. Cluster tightly; spawns are the expensive route.
+- Outside-world facts: call `web_search` directly.
 - Cheap lookups: `read`/`grep` inline.
-- Only the main session may ask; every spawn carries the exact facts to return.
+- The main session is where questions happen: every spawn carries the exact facts to return, and comes back into the next round.
 
-## Completion
+## Done
 
-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 the project's knowledge base, or a log markdown file, and refresh the ledger file to final form.
+The frontier is empty and nothing sits blocked. Distil the ledger into a **brief**: one line per decision, verdict plus rationale, grouped by branch. Put it in chat, then one closing `ask`: "Proceed on this brief?" Nothing executes before that yes. After it, fold the brief into the project's knowledge base, or a log markdown file, wherever the project keeps its decisions.