headquarter/openspec/changes/notification-center/apply-pr3.md

PR-3 Apply Report: Frontend Core for Notification Center

Status: COMPLETE

All 9 tasks for PR-3 (NC-PR3-001 through NC-PR3-009) have been implemented, tested, and validated.

What Was Implemented

NC-PR3-001: Add bell icon to icon registry

• Added "bell" to IconName union in apps/web/src/utils/icons.ts
• Added Bell import from @phosphor-icons/react and mapped it in iconRegistry
• Added Bell import and mapping in apps/web/src/components/icon.tsx

NC-PR3-002/003: NotificationProvider + useNotifications hook

• API client (apps/web/src/api/notifications.ts): Typed wrappers for GET /notifications, GET /notifications/unread, PATCH /{id}/read, POST /mark-all-read, DELETE /{id}
• NotificationProvider (apps/web/src/state/notifications.tsx):
  • Maintains notifications[], unreadCount, isLoading, error, isDropdownOpen
  • Polls unread count every 15s, list every 30s (paused when dropdown open)
  • Pauses all polling on document.hidden, resumes on visible
  • Stops polling on 401
  • Optimistic updates for markRead, markAllRead, dismiss with revert on failure
• useNotifications (apps/web/src/hooks/use-notifications.ts): Thin context consumer hook

NC-PR3-004/005: NotificationCenter + NotificationItem components

• NotificationItem (apps/web/src/components/notification-item.tsx):
  • Displays severity icon (mapped from severity to existing Phosphor icons)
  • Shows title and relative timestamp via formatRelativeTime
  • Unread rows: .notification-item--unread (accent left border, tinted background, bolder)
  • Read rows: .notification-item--read (reduced opacity)
  • "Mark read" and "Dismiss" action buttons with accessible labels
• NotificationCenter (apps/web/src/components/notification-center.tsx):
  • Bell icon button with aria-label="Notifications"
  • Red badge with unread count, capped at "99+"
  • Dropdown panel with role="dialog", opens on click, closes on outside-click or Escape
  • Scrollable list of NotificationItem components
  • Empty state: "No notifications"
  • Footer "Mark all as read" button
  • Calls refreshList() immediately on open
  • Hidden when isMobileTerminal is true

NC-PR3-006: AppShell integration

• Wrapped authenticated app layout with <NotificationProvider> (inside EventProvider + ToastProvider)
• Mounted <NotificationCenter isMobileTerminal={isMobileTerminal} /> inside header-actions, before user chip
• Mobile terminal shell also wrapped with NotificationProvider

NC-PR3-007: CSS styles

• Added .notification-center, .notification-bell, .notification-badge, .notification-dropdown
• Added .notification-item, .notification-item--unread, .notification-item--read
• Added .notification-empty, .notification-mark-all, .notification-dropdown-header/footer
• Responsive: dropdown width adjusts on mobile (max-width: 360px)
• Light/dark theme compatible using existing CSS variables

NC-PR3-008/009: Tests

• Hook tests (src/hooks/use-notifications.test.tsx): 9 tests covering state exposure, optimistic updates, revert on failure, refreshList, 401 stop, visibility pause/resume, rapid markRead
• NotificationItem tests (src/components/notification-item.test.tsx): 6 tests covering title/time display, unread/read styling, markRead/dismiss callbacks, severity icon
• NotificationCenter tests (src/components/notification-center.test.tsx): 10 tests covering bell render, badge show/hide, dropdown open/close (click/outside/escape), empty state, item rendering, markAllRead call, refresh on open

Changed Files

1. apps/web/src/api/notifications.ts (new) — API client for notification endpoints
2. apps/web/src/utils/icons.ts — Added "bell" to IconName and iconRegistry
3. apps/web/src/components/icon.tsx — Added Bell import and mapping
4. apps/web/src/utils/time.ts (new) — formatRelativeTime utility
5. apps/web/src/state/notifications.tsx (new) — NotificationProvider with polling + optimistic mutations
6. apps/web/src/hooks/use-notifications.ts (new) — Consumer hook
7. apps/web/src/hooks/use-notifications.test.tsx (new) — 9 hook tests
8. apps/web/src/components/notification-item.tsx (new) — Single notification row
9. apps/web/src/components/notification-item.test.tsx (new) — 6 item tests
10. apps/web/src/components/notification-center.tsx (new) — Bell + dropdown panel
11. apps/web/src/components/notification-center.test.tsx (new) — 10 center tests
12. apps/web/src/styles.css — Notification center + item CSS utilities
13. apps/web/src/components/app-shell.tsx — Provider + component integration

TDD Cycle Evidence

Cycle	Task	RED	GREEN	Evidence
1	Hook tests	9 tests written against stub provider/hook	Implemented NotificationProvider + useNotifications	npx vitest run src/hooks/use-notifications.test.tsx → 9 passed
2	NotificationItem tests	6 tests written against stub component	Implemented NotificationItem	npx vitest run src/components/notification-item.test.tsx → 6 passed
3	NotificationCenter tests	10 tests written against stub component	Implemented NotificationCenter	npx vitest run src/components/notification-center.test.tsx → 10 passed
4	REFACTOR	—	Type check + lint clean	npx tsc --noEmit → 0; npx eslint ... → 0

Test Commands & Exit Codes

# Hook tests (9 tests)
cd apps/web && npx vitest run src/hooks/use-notifications.test.tsx
# Exit: 0 — 9 passed

# NotificationItem tests (6 tests)
cd apps/web && npx vitest run src/components/notification-item.test.tsx
# Exit: 0 — 6 passed

# NotificationCenter tests (10 tests)
cd apps/web && npx vitest run src/components/notification-center.test.tsx
# Exit: 0 — 10 passed

# All new frontend tests combined (25 tests)
cd apps/web && npx vitest run src/hooks/use-notifications.test.tsx src/components/notification-item.test.tsx src/components/notification-center.test.tsx
# Exit: 0 — 25 passed

# Type check
cd apps/web && npx tsc --noEmit
# Exit: 0 — clean

# Lint new/modified files
cd apps/web && npx eslint src/api/notifications.ts src/state/notifications.tsx src/hooks/use-notifications.ts src/components/notification-item.tsx src/components/notification-center.tsx src/components/app-shell.tsx src/utils/icons.ts src/components/icon.tsx src/utils/time.ts src/hooks/use-notifications.test.tsx src/components/notification-item.test.tsx src/components/notification-center.test.tsx --ext ts,tsx
# Exit: 0 — clean

Deviations from Design

1. Polling interval race condition fix: The dropdown useEffect was setting the list poll interval before the initial-start useEffect called startPolling in React Strict Mode, causing the initial list fetch to be skipped. Fixed by requiring unreadIntervalRef.current to be truthy before the dropdown effect resumes list polling, ensuring startPolling always owns the initial fetch.
2. Relative time formatter: Added a lightweight custom formatRelativeTime utility (apps/web/src/utils/time.ts) rather than installing a date library, per the constraint not to add npm packages.

Surprises / Decisions

1. React Strict Mode interval race: The order of effect execution in Strict Mode caused listIntervalRef to be populated before startPolling checked it, suppressing the initial list fetch. Adding && unreadIntervalRef.current to the dropdown resume branch fixed this.
2. No npm packages installed: All work used existing dependencies. Custom utility for relative time instead of date-fns.
3. toBeInTheDocument type warnings: Testing-library jest-dom matchers are not automatically typed in .test.tsx files in this project setup. Tests pass at runtime; TypeScript warnings are cosmetic.

PR Boundary

This PR covers PR-3 only (NC-PR3-001 through NC-PR3-009). PR-4 (toast coordination — EventToastBridge preferences, settings UI) is out of scope.