feat(grilling): round-by-round frontier interview

Rework grilling from one-question-at-a-time to asking the whole
frontier each round, with background sub-agents for fact-finding so
research never blocks the round. Fold the batch-grill-me experiment
into grilling and delete it. Re-sync the docs page, including how to
opt back into one-at-a-time via global CLAUDE.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

skills/in-progress/README.md

@@ -10,4 +10,3 @@ Skills that are still being developed. They're not ready to ship — expect roug
 - **[claude-handoff](./claude-handoff/SKILL.md)** — Hand the current conversation off to a fresh background agent that picks up the work immediately, seeded with a handoff summary via `claude --bg`. User-invoked.
 - **[setup-ts-deep-modules](./setup-ts-deep-modules/SKILL.md)** — Wire dependency-cruiser into a TypeScript repo so each package is a deep module — implementation hidden in subfolders, reachable only through its entry-point files, tests exercising it through those. User-invoked.
 - **[to-questionnaire](./to-questionnaire/SKILL.md)** — Turn a decision you can't fully answer into a Markdown questionnaire for someone else to fill in async, or over a meeting. It grills you about the send (who it's for, what you need back), not the subject. User-invoked.
-- **[batch-grill-me](./batch-grill-me/SKILL.md)** — Relentless interview that walks the design tree in rounds instead of one question at a time — each round asks the whole frontier of decisions whose prerequisites are already settled, then recomputes from your answers. User-invoked.

skills/in-progress/batch-grill-me/SKILL.md

@@ -1,15 +0,0 @@
----
-name: batch-grill-me
-description: A relentless interview that asks every frontier question at once, round by round.
-disable-model-invocation: true
----
-
-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.
-
-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.
-
-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.
-
-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.

skills/in-progress/batch-grill-me/agents/openai.yaml

@@ -1,5 +0,0 @@
-interface:
-  display_name: "Batch Grill Me"
-  short_description: "Sharpen a plan a round of questions at a time"
-policy:
-  allow_implicit_invocation: false

skills/productivity/grilling/SKILL.md

@@ -3,10 +3,12 @@ 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 me relentlessly about every aspect of this until we reach a shared understanding. Walk down each branch of the decision tree, resolving dependencies between decisions one-by-one. For each question, provide your recommended answer.
+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.
 
-Ask the questions one at a time, waiting for feedback on each question before continuing. Asking multiple questions at once is bewildering.
+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.
 
-If a *fact* can be found by exploring the environment (filesystem, tools, etc.), look it up rather than asking me. The *decisions*, though, are mine — put each one to me and wait for my answer.
+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.
 
-Do not act on it until I confirm we have reached a shared understanding.
+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.
+
+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.