-- v1.4.25 W14b — onboarding wizard resume-state.
--
-- Adds `onboarding_step` to the `users` table so the rebuilt multi-step
-- wizard at `/onboarding/[step]` can resume the user at the highest
-- step they reached. Without this column, closing the tab mid-flow
-- wipes progress and forces users back to step 0.
--
-- Step encoding (mirrors `src/components/onboarding/OnboardingShell.tsx`
-- and `src/app/onboarding/[step]/page.tsx`):
--   0 = welcome    (carousel / value-prop intro)
--   1 = goals      ("what do you want to track?")
--   2 = source     ("connect a source" — Withings / Apple Health / manual)
--   3 = baseline   (first measurement / sync confirmation)
--   4 = done       (success screen; same write that flips
--                   `onboarding_completed_at` from NULL to NOW())
--
-- Existing rows are backfilled to 0 by PostgreSQL's fast-path
-- `ADD COLUMN ... DEFAULT` (PG11+), which materialises the default
-- without rewriting the table — every pre-W14b user lands at step 0
-- in O(1) time. The column ships nullable purely so the DDL stays
-- additive on every replica; Migration 0060 follows up by flipping
-- it to NOT NULL once the deploy has rolled.
--
-- The `IF NOT EXISTS` guards make the migration idempotent — if the
-- column landed via a prior dev-DB hand-edit, the migration still
-- runs cleanly to completion.
ALTER TABLE "users"
  ADD COLUMN IF NOT EXISTS "onboarding_step" INTEGER DEFAULT 0;