feat: graduate wizard into the engineering bucket

Move `wizard` out of in-progress into `engineering/` and wire it up as a
promoted skill: plugin.json entry, top-level + Engineering READMEs under
User-invoked, a docs page at docs/engineering/wizard.md, and a Standalone
route in ask-matt for the steps only a human can take.

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

README.md

@@ -185,6 +185,7 @@ Skills I use daily for code work.
 - **[to-tickets](./skills/engineering/to-tickets/SKILL.md)** — Break any plan, spec, or conversation into a set of tracer-bullet tickets, each declaring its blocking edges — written as text in a local file, or as native blocking links on a real tracker.
 - **[implement](./skills/engineering/implement/SKILL.md)** — Build the work described by a spec or set of tickets, driving `/tdd` at pre-agreed seams and closing out with `/code-review` before committing.
 - **[wayfinder](./skills/engineering/wayfinder/SKILL.md)** — Plan a huge chunk of work, more than one agent session can hold, as a shared map of investigation tickets on the issue tracker — resolve them one at a time until the way to the destination is clear.
+- **[wizard](./skills/engineering/wizard/SKILL.md)** — Generate an interactive bash wizard that walks a human through a manual procedure — third-party setup, a one-off migration, an A→B state transition — opening each URL, capturing values, confirming every step, and writing `.env` files and GitHub Actions secrets.
 
 **Model-invoked**