feat: Phase 4 — five-step wizard UI with R-only badges and data-path …

[bakodramane]

…split

Pre-work (data path split):

• UserInputs.censusDataPath now exclusively for unit-level census microdata
• UserInputs.areaDataPath added for area-level direct estimates + auxiliaries
• codegen.ts buildTokenMap updated: AREA_DATA uses areaDataPath, CENSUS_DATA uses censusDataPath (previously both shared the same field)
• codegen.test.ts: FH_INPUTS updated to use areaDataPath

Wizard UI (src/wizard/):

• WizardContext.tsx — WizardState + useReducer with 12 action types; RESET action
• Tooltip.tsx — hover tooltip component + InfoIcon (? badge)
• Step1Import.tsx — CSV upload via papaparse (drag-and-drop + click), manual row-by-row entry, preview table with remove; validates ≥1 variable
• Step2Roles.tsx — role/type dropdowns per variable; auto-suggests roles from variable name/type (weight, area-id, coordinate, direct-est, direct-var); validates exactly 1 target, ≥1 area-id, ≥1 auxiliary; role legend with tooltips
• Step3Availability.tsx — checkboxes for all 9 DataAvailability flags with plain-language labels and tooltips; target-type radio (continuous/binary/ proportion/count/poverty/unknown); Stata version number input
• Step4Methods.tsx — ranked method cards calling recommend(); badges: Area-level, Unit-level, Model-assisted, Bayesian, Robust, Spatial, R only (always visible), Stata v14 workaround; expandable Why this method? panel; single selection + optional comparison; R-only badge is immediate (not in expandable panel)
• Step5Generate.tsx — variable summary; data path overrides (survey, census, area); nSimulations/mseMethod overrides; code preview in

   blocks; Download R button (always enabled); Stata button disabled for R-only methods (hb-fh, m-quantile, mqgwr, reblup, hb-unit) replaced by plain-language note; yellow fallback banner when usedFallback

• Wizard.tsx — top progress bar (5 steps), Back/Next navigation, Start over; validation-gated Next button; replaces App.tsx placeholder

isROnly utility: entry.stataCommand.startsWith((no) — covers all 5 R-only methods (hb-fh, m-quantile, mqgwr, reblup, hb-unit) without hardcoding IDs.

E2E smoke test (e2e/wizard.spec.ts):

• Uploads test-codebook.csv (7 variables including target, area-id, auxiliaries, weight, direct-est, direct-var)
• Assigns roles via dropdown interaction
• Ticks availability flags (microdata, area aggregates, weights, census auxiliaries)
• Verifies FH-EBLUP card is present in the recommendation list
• Selects FH-EBLUP and advances to Step 5
• Triggers R script download and asserts filename ends in .R

All checks pass:

• npm run build PASS
• npm run lint PASS (0 warnings)
• npm test PASS (430 unit tests)
• playwright test e2e/wizard.spec.ts PASS (1/1)