[aicayzer]

Summary

Adds a guide to moving every item of one type to another with marfa types move and POST /types/{id}/move, and makes "Define a type" and "Sync a folder" agree with it. Follows withmarfa/marfa#2395, which adds the move and makes a type delete refuse while folders, views or webhooks name the type.

Changes

• New guide, "Move items to another type": the dry run, the move, the property patch, what happens to items it can't move, what remains once the job ends (remaining, remaining_hidden, the first 100 refusals in errors and every one counted in errored), the settings it rewrites and only once no item of the old type remains, the reasons a move is blocked (including a stored filter that doesn't parse or would grow too long), settings your key can't read named without an ID, what the key needs, key and app grants, and deleting the old type.
• "Define a type": a type's identifier never changes, and a rename is a move. The delete section says a plain delete refuses while items or settings name the type, what details holds (without the ID of a setting your key can't read), and that force=true leaves both as they are.
• "Sync a folder": a move changes a folder's settings too.

Testing

• pnpm test: 699 of 700 pass; the content lint passes.
• src/lib/command-check.test.ts fails on marfa types move until a Marfa release with feat(server): move a type's items in one step marfa#2395 is synced. CI may fail until then.

Not tested: the full site build.

Notes for reviewers

• Hold this until feat(server): move a type's items in one step marfa#2395 merges and the sync pull request lands, then rerun CI.
• Every name, field, error and reason was checked against the contract and the server code in feat(server): move a type's items in one step marfa#2395.

Checklist

• The title is a scoped Conventional Commit.
• New behavior has a test that was seen failing first, or no test was needed and the reason is above. No test: a docs page, held by the content lint and the command check.
• Docs, comments and the contract still say what is true after this change.

[aicayzer]

Review: checks only