Refactor coverage guidelines wizard: Zustand persist → RHF + React Query

[jcleow]

Context

The coverage guidelines questionnaire wizard (coverageGuidelinesStore.ts) currently uses Zustand with persist middleware (localStorage) for both form state and cross-component shared state. This works but has several issues:

• No form validation — inputs accept any value with no error feedback
• Stale localStorage bugs — adding new fields causes NaN for users with old persisted data (see ?? 0 guards throughout GuidelinesTab.tsx)
• Doesn't follow project conventions — CLAUDE.md specifies RHF for forms + Zod for validation
• Will be redundant — once backend persistence is implemented (#TBD), localStorage persistence should be removed entirely

Current Architecture

Wizard steps (5 components)
  → Zustand store actions (setLifeTpdAnswers, setCriticalIllnessAnswers, etc.)
    → persist middleware → localStorage
      → consumed by: CoverageJourney, JourneyTab, ConfiguredGuidelinesView, etc.

Target Architecture

Wizard steps (5 components)
  → React Hook Form useForm() per step
    → Zod schema validation per step
      → on step complete: React Query mutation → backend API
        → React Query cache = shared state for all consumers

Migration Steps

Phase 1: Add RHF + Zod to wizard steps (can do before backend)

• Create Zod schemas for each questionnaire section (hospitalizationSchema, lifeTpdSchema, etc.)
• Wrap each wizard step component with useForm() + the relevant schema
• Add inline validation errors (required fields, min/max ranges)
• On "Continue", validate step → sync to Zustand store (keep store as intermediate)

Phase 2: Backend persistence (separate issue/PR)

• Implement insurance backend CRUD APIs (see spec/insurance-backend-persistence.md)
• Add React Query hooks: useCoverageGuidelinesQuery, useCoverageGuidelinesMutation
• Replace Zustand persist → React Query as source of truth

Phase 3: Remove Zustand store

• Consumers (CoverageJourney, JourneyTab, etc.) read from React Query cache instead of Zustand
• Remove coverageGuidelinesStore.ts entirely
• Remove coverage-guidelines-storage from localStorage

Files Involved

File	Change
frontend/src/stores/coverageGuidelinesStore.ts	Eventually remove
frontend/src/components/insurance/tabs/GuidelinesTab.tsx	Add RHF per wizard step
frontend/src/hooks/queries/useCoverageGuidelinesQuery.ts	New — React Query hooks
frontend/src/types/insurance-schemas.ts	New — Zod validation schemas

Related

• Backend persistence spec: spec/insurance-backend-persistence.md
• Similar pattern already used in: OnboardingWizardModal (RHF + Zod)

[linear]

ASS-78