feat: graduate to-questionnaire into the productivity bucket

Move `to-questionnaire` out of in-progress into `productivity/` and wire
it up as a promoted skill: plugin.json entry, top-level + Productivity
READMEs under User-invoked, a docs page at
docs/productivity/to-questionnaire.md, and a Standalone route in
ask-matt framing it as the inverse of /grill-me.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/engineering/ask-matt/SKILL.md

@@ -70,6 +70,7 @@ Off the main flow entirely.
 - **`/grill-me`** — the same relentless interview as `/grill-with-docs`, but for when you have **no codebase**. Stateless: it saves nothing locally, builds no `CONTEXT.md`. Reach for it to sharpen any plan or design that doesn't live in a repo.
 - **`/prototype`** — a small, throwaway program that answers one design question: does this state model feel right, or what should this UI look like. Throwaway from day one — keep the answer, delete the code. It's the detour in step 2 of the main flow, but reach for it any time a design question is hard to settle on paper.
 - **`/research`** — delegate reading legwork to a **background agent**: it investigates a question against **primary sources**, then leaves a cited Markdown file in the repo. Keep working while it reads. The file it produces is something to take *into* the main flow at `/grill-with-docs` — research feeds the thinking, it doesn't replace it.
+- **`/to-questionnaire`** — when the thing blocking you isn't in your head or the codebase but in **someone else's**, this writes them a questionnaire to fill in. It's the inverse of `/grill-me`: instead of interviewing you about the subject, it interviews you about the **send** — who it's going to, what you need back — and aims the questions at the gap. What comes back is material for `/grill-with-docs` or `/to-spec`.
 - **`/teach`** — learn a concept over multiple sessions, using the current directory as a stateful workspace.
 - **`/writing-for-agents`** — reference for writing documents agents consume: skills, AGENTS.md, pointed-at docs.
 

skills/in-progress/README.md

@@ -9,4 +9,3 @@ Skills that are still being developed. They're not ready to ship — expect roug
 - **[writing-shape](./writing-shape/SKILL.md)** — Take a markdown file of raw material and shape it into an article paragraph by paragraph, arguing format choices at each step.
 - **[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.

skills/productivity/README.md

@@ -9,6 +9,7 @@ Reachable only when you type them (Claude Code: `disable-model-invocation: true`
 - **[grill-me](./grill-me/SKILL.md)** — Get relentlessly interviewed about a plan or design until every branch of the decision tree is resolved.
 - **[handoff](./handoff/SKILL.md)** — Compact the current conversation into a handoff document so another agent can continue the work.
 - **[teach](./teach/SKILL.md)** — Teach the user a new skill or concept over multiple sessions, using the current directory as a stateful teaching workspace.
+- **[to-questionnaire](./to-questionnaire/SKILL.md)** — Turn a decision you can't answer alone into a Markdown questionnaire for the one person who can — filled in async, or together over a meeting.
 - **[writing-for-agents](./writing-for-agents/SKILL.md)** — Writing documents for agents: skills, AGENTS.md/CLAUDE.md, and any doc an agent reaches by a pointer.
 
 ## Model-invoked