feat(PBI-76): user-settings DB-store infrastructure (Phase 0) (#185)

* docs(PBI-76): plan for user-settings DB-store

Persists view/filter prefs in User.settings (Json) instead of
localStorage. SSR-correct hydration, cross-tab sync via
LISTEN/NOTIFY + SSE, cross-device persistence.

Phased: 0=infra, 1=migrate flicker sources, 2=cookie consolidation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): User.settings json column + migration

Adds JSONB column to users table for persistent user prefs.
Idempotent SQL — safe on databases where column already exists.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): user-settings types and merge helpers

Zod schema for User.settings shape (views/devTools), deep-merge
helper that replaces arrays and merges nested objects, and a
safe parser that returns defaults on invalid input.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): updateUserSettingsAction with notify

Validates patch via Zod, deep-merges with current settings in
a transaction, persists to DB, and emits pg_notify on
scrum4me_changes for cross-tab/cross-device sync. Demo accounts
get 403, unauthenticated 401, invalid input 422.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): user-settings zustand store with optimistic flow

Hydrate from prop (SSR-correct), setPref via path with optimistic
update + rollback on server error, applyServerPatch for SSE-driven
cross-tab updates. Demo accounts skip server-write entirely.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): SSE route for user-settings

User-scoped /api/realtime/user-settings stream that filters
scrum4me_changes notifications on kind=user_settings and matching
userId. Forwards the patch as a data: event so other tabs can
applyServerPatch without re-fetching settings.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(PBI-76): user-settings bridge mounted in app layout

Hydrates the zustand store with the user's persisted settings via
prop (SSR-correct, no flicker). Opens an EventSource to
/api/realtime/user-settings so changes from other tabs/devices
flow into the same store. Demo accounts skip the SSE subscription.

Layout now selects user.settings alongside the other user fields,
no extra DB roundtrip.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(PBI-76): user-settings lib/action/store coverage

22 vitest cases covering merge semantics (no mutation, array
replace, nested merge), Zod schema strictness, server action
auth/demo/validation paths, and the optimistic store flow
including rollback and demo-mode skip.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(PBI-76): sync package-lock to v1.3.3

Lockfile drifted after @prisma/client reinstall during the
schema regenerate. No dependency changes — just the version
field tracking package.json bumped in #184.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

actions/user-settings.ts

@@ -0,0 +1,62 @@
+'use server'
+
+import { cookies } from 'next/headers'
+import { getIronSession } from 'iron-session'
+import { Prisma } from '@prisma/client'
+import { prisma } from '@/lib/prisma'
+import { SessionData, sessionOptions } from '@/lib/session'
+import {
+  UserSettingsSchema,
+  mergeSettings,
+  parseUserSettings,
+  type UserSettings,
+} from '@/lib/user-settings'
+
+async function getSession() {
+  return getIronSession<SessionData>(await cookies(), sessionOptions)
+}
+
+export type UpdateUserSettingsResult =
+  | { success: true; settings: UserSettings }
+  | { error: string; code: 401 | 403 | 422; fieldErrors?: Record<string, string[]> }
+
+export async function updateUserSettingsAction(
+  patch: Partial<UserSettings>,
+): Promise<UpdateUserSettingsResult> {
+  const session = await getSession()
+  if (!session.userId) return { error: 'Niet ingelogd', code: 401 }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus', code: 403 }
+
+  const parsed = UserSettingsSchema.partial().safeParse(patch)
+  if (!parsed.success) {
+    return {
+      error: 'Ongeldige settings-patch',
+      code: 422,
+      fieldErrors: parsed.error.flatten().fieldErrors as Record<string, string[]>,
+    }
+  }
+
+  const merged = await prisma.$transaction(async (tx) => {
+    const user = await tx.user.findUnique({
+      where: { id: session.userId! },
+      select: { settings: true },
+    })
+    const current = parseUserSettings(user?.settings)
+    const next = mergeSettings(current, parsed.data)
+    await tx.user.update({
+      where: { id: session.userId! },
+      data: { settings: next as unknown as Prisma.InputJsonValue },
+    })
+    return next
+  })
+
+  await prisma.$executeRaw`
+    SELECT pg_notify('scrum4me_changes', ${JSON.stringify({
+      kind: 'user_settings',
+      userId: session.userId,
+      patch: parsed.data,
+    })}::text)
+  `
+
+  return { success: true, settings: merged }
+}