docs(explore): pages say explore never writes files, but capture creates a change

[clay-good]

Six pages say explore creates no artifacts. It does, on request: the capture branch runs openspec new change and writes the artifacts you ask for. Has since #668 / #720.

Wrong:

File	Line	Says
docs-lab/start/quickstart.md	30	"It writes no code and no files." (live on the docs site)
docs/explore.md	32-34	"It does not: Create a change folder. / Write any artifacts…"
docs/workflows.md	143	"Explore creates no artifacts and writes no code."
docs/glossary.md	49	"…creating no artifacts and writing no code."
docs/commands.md	129	"No artifacts are created during exploration"
docs/examples.md	71	"…no structure and no artifacts created."

Right, copy this: docs-lab/reference/skills.md:64 — "Nothing by default. It reads and investigates only. On request it captures insights: a new change proposal under openspec/changes/<name>/… Never code."

Keep "explore never implements" — that part is true and load-bearing. Only "no artifacts, ever" is wrong.

Both trees need it: docs/ is what README links today, docs-lab/start/quickstart.md is published to the site now. Docs-only.

Timely because #1832 removed the second confirmation prompt that used to sit between reading "it does not create a change folder" and one appearing.