docs: add human-facing pages for the remaining 22 promoted skills

Adds a docs page for every promoted skill that lacked one, following
.agents/writing-docs.md and using docs/engineering/to-prd.md as the
worked exemplar. Covers all of engineering/ (bar to-prd, already done),
productivity/, and misc/.

Each page states its load-bearing constraint, its invocation mode and
trigger boundary, surfaces the skill's leading word, and routes back to
ask-matt so the set forms a connected router with no dead ends.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/engineering/to-issues.md

@@ -0,0 +1,43 @@
+Quickstart:
+
+```bash
+npx skills add mattpocock/skills --skill=to-issues
+```
+
+```bash
+npx skills update to-issues
+```
+
+[Source](https://github.com/mattpocock/skills/tree/main/skills/engineering/to-issues)
+
+## What it does
+
+`to-issues` breaks a plan, spec, or PRD into a set of independently-grabbable issues and publishes them to your project's issue tracker, in dependency order.
+
+The load-bearing constraint: every issue is a **tracer bullet** — a thin *vertical* slice that cuts through all integration layers end-to-end (schema, API, UI, tests), never a horizontal slice of one layer. A completed slice is demoable or verifiable on its own, which is what makes the resulting tickets safe to hand to independent agents.
+
+## When to reach for it
+
+You invoke this by typing `/to-issues` — the agent won't reach for it on its own.
+
+Reach for it once you have an agreed plan or a written spec and you want it split into tickets an agent can pick up. Point it at the conversation, or pass an existing issue reference and it fetches the body and comments first. If the change hasn't been written up as a spec yet, produce one first — for that, use [to-prd](https://aihero.dev/skills-to-prd).
+
+## Prerequisites
+
+`to-issues` publishes into your issue tracker, so [setup-matt-pocock-skills](https://aihero.dev/skills-setup-matt-pocock-skills) must have configured the tracker and its triage label vocabulary for this repo first. It applies the ready-for-agent triage label itself as it publishes.
+
+## Vertical slices, not horizontal ones
+
+The whole skill turns on one distinction. A **horizontal** slice ships one layer of the change — all the schema, or all the API — and nothing works until every layer lands. A **vertical** slice, the tracer bullet, ships one narrow path through *every* layer at once, so it can be demoed the moment it's done.
+
+Before slicing, `to-issues` looks for prefactoring — "make the change easy, then make the easy change" — and orders that work first. It then quizzes you on the breakdown (granularity, dependencies, what to merge or split) before writing anything, and publishes blockers first so each issue's "Blocked by" field can reference a real ticket.
+
+## Where it fits
+
+`to-issues` is a step in the main build chain:
+
+```txt
+grill-with-docs → to-prd → to-issues → tdd
+```
+
+It sits between [to-prd](https://aihero.dev/skills-to-prd), which hands it a settled spec with user stories to slice against, and [tdd](https://aihero.dev/skills-tdd), which implements each independently-grabbable issue test-first. When you're unsure which skill or flow fits, [ask-matt](https://aihero.dev/skills-ask-matt) routes you.