feat(admin): resurface setup wizard when a release adds setup

Imported from GitHub pull request El-SaMa/oma#116 by @El-SaMa.

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Summary

• The setup wizard was dismissed with a permanent boolean, so once hidden it never came back, even when a new OMA release added essential setup. Now dismissal is pinned to a setup signature (SETUP_WIZARD_REVISION + sorted step ids).
• When a release adds/renames a step, or we bump SETUP_WIZARD_REVISION, the signature changes and the wizard resurfaces on the dashboard banner and the setup page until the operator finishes or hides it again.
• Legacy boolean dismissals resurface once after this ships (intended for the release).
• Banner and wizard show a "New in this release" hint when resurfaced.

How to trigger a resurface in future releases

• Add a new step in setup-checklist.ts (auto-changes the signature), or
• Bump SETUP_WIZARD_REVISION for a feature that has no dedicated step.

Files

• lib/admin/setup-wizard-store.ts - signature-aware dismissal.
• lib/admin/setup-checklist.ts - SETUP_WIZARD_REVISION, computeSetupSignature, signature on the checklist.
• app/admin/settings/setup/*, app/admin/page.tsx - wire signature + resurfaced state.
• components/admin/setup-wizard*.tsx - resurfaced hint.
• messages/{en,fi,sv}.json - new keys.

Test plan

• Fresh org: wizard + banner show until required steps done.
• Dismiss on dashboard: banner hides; setup page offers restore.
• Bump SETUP_WIZARD_REVISION (or add a step): banner + wizard resurface with the "New in this release" hint.
• Finish or dismiss again: hides for the new signature.
• pnpm i18n:check and tsc pass.