feat: Lookup control in Table and Modify-structure wizards (#62)

[DDecoene]

Summary

The Assistant sidebar's New-table and Modify-structure wizards gain an optional per-column "lookup" input, accepting either TABLE.COLUMN [DISPLAY COLUMN] or a quoted list — so declaring a LOOKUP no longer requires dropping into raw W3Script syntax. A shared lookupClause() helper (exported from TableWizard.ts, reused by ModStructWizard.ts) parses the input and folds the resulting clause into every emitted CREATE TABLE/ALTER TABLE ADD/ALTER TABLE ALTER command.

This is the last issue in the v1.3.0 lookup-columns milestone. With this merged, the language (#58), enforcement + BROWSE (#60), field-bound forms (#59), two demo apps (#61), and now the GUI wizards all agree on one constraint, declared once, on the column.

Plan: docs/superpowers/plans/2026-07-11-lookup-columns.md (Task 13)

Closes #62.

Test plan

• npm test — 446/446 vitest pass
• npm run build — clean typecheck + build
• npx playwright test — 95/96 pass. The one failure (assistant.spec.ts › "open database via picker") is the same pre-existing environment flake already documented and verified against unmodified main in PR feat: demos adopt LOOKUP columns — overtime + CRM (#61) #66 — unrelated to this change.
• New Playwright case drives the wizard end-to-end: fills the lookup field, asserts the exact preview text, submits, then opens BROWSE and confirms the created column's grid editor is an in-viewport <select> with exactly the declared option list