wip(settings): formula field guided builder follow-up

[akira69]

Summary

This PR defines the guided-builder authoring layer for Formula Extra Fields on top of #14.

Intent

• Preserve the raw JSON editor and preview workflow while making references, operators, and helpers directly insertable.
• Add compatibility-driven guidance so authors can assemble valid expressions with less manual JSON construction.
• Keep authoring grounded in backend-supported paths and helper inputs.
• Align the help page and in-app copy with a guided authoring mental model.

Review Focus

• Are the guided insertion flows coherent and low-friction?
• Does Compatible Inputs steer expression building in a useful way?
• Is raw JSON editing still preserved as a first-class path?
• Does the copy consistently explain guided authoring without hiding the underlying JSON Logic?

Screenshots

Settings page with the guided-builder summary:

Formula editor with a guided token flow and Compatible Inputs:

Validation

• ./node_modules/.bin/eslint src/pages/help/index.tsx src/pages/settings/formulaFieldsSettings.tsx
• VITE_APIURL=/api/v1 npm run build
• local browser validation on http://localhost:2885
• opened the Formula Extra Fields settings page and confirmed the guided-builder copy renders correctly
• opened an existing formula field editor and confirmed Help: Building Formula Expressions and Compatible Inputs are visible
• confirmed grouped references/operators/helpers are interactive and insertable
• opened /help#formula-fields and verified the help page describes guided insertion and Compatible Inputs
• captured fresh screenshots from the running local build

Test Checklist

• Frontend lint passed for touched guided-builder files
• Frontend build passed with VITE_APIURL=/api/v1
• Formula editor renders the guided-builder surface on localhost:2885
• Help page wording matches the guided-builder workflow
• Screenshot assets were updated for the current PR state

Stack Context

• Base PR: wip(settings): formula fields JSON-first base and preview #14 wip(settings): formula fields JSON-first base and preview
• This PR layers guided insertion and compatibility-driven field assistance on top of that base.