feat: notification digest batching, creators search, postgres backup drill, rate-limit tests

[kelly-musk]

Summary

Closes #740, #731, #730, #728

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#740 — Notification digest batching

Reduces noise by collapsing repeated same-type events within a 5-minute window into a single notification instead of creating one per event.

Backend

• NotificationsService: added foldIntoDigest / openDigestWindow — second enqueue within the window updates the existing notification's count/title/body in-place
• buildSubscriptionLifecycleTemplate accepts digestCount and returns plural titles ("3 subscriptions renewed")
• Notification entity: new digest_count (int, default 1) and digest_event_times (jsonb) columns
• Migration: 1745100000000-AddDigestColumnsToNotifications
• Email only sent for the first event in a window

Frontend

• NotificationItem: count pill badge when digest_count > 1
• NotificationDetail: "N events batched" section with individual timestamps
• Mock data updated with realistic digest examples

Tests

• 5 new unit tests: plural template titles, fold with no/open/expired window, missing notification, second enqueue folding
• 2 new e2e tests: digest badge visible in list, digest detail modal shows batched events

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#731 — Creators search by handle/display name

Backend

• Fixed broken searchCreators (dead code after early return, no q filter applied, wrong pagination shape)
• Now applies LOWER(display_name) LIKE :search OR LOWER(username) LIKE :search prefix match
• Page-based skip/take pagination, ordered by username ASC
• PaginatedResponseDto extended with total, page, totalPages fields

Frontend

• New frontend/src/lib/api/creators.ts — searchCreators({ q?, page?, limit? })
• DiscoverContent calls real API when NEXT_PUBLIC_USE_CREATORS_API=true, falls back to mock otherwise

Tests

• Existing creators.service.spec.ts tests now pass (they were written against the intended behavior)

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#730 — Postgres backup / restore drill

• scripts/pg-backup-restore.sh: backup, restore, and drill subcommands
  • drill: backup → restore into temp DB → row-count verification → auto-cleanup
  • Password via PGPASSWORD (never on CLI)
• docs/POSTGRES_BACKUP_RESTORE.md: runbook with pre-deploy checklist, restore decision tree, security notes
• CI: new db-backup-drill job in .github/workflows/ci.yml (runs after backend-migrations)

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#728 — Rate limit integration tests

• backend/test/rate-limit.e2e-spec.ts: self-contained e2e suite using the real ThrottlerGuard with stub controllers and tiny limits (2–5) for fast, deterministic 429 triggering
  • Auth endpoints → 429 after limit exceeded
  • Health endpoints → never throttled (10 requests all 200)
  • General endpoint (long tier) → 429 after limit
  • 429 response shape: statusCode, message, Retry-After header
• Fixed latent bug: auth throttle tier was used in @Throttle({ auth: ... }) decorators but never registered in ThrottlerModule.forRoot — added { name: 'auth', ttl: 60000, limit: 5 }

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Files changed

File	Change
backend/src/notifications/notifications.service.ts	Digest batching logic
backend/src/notifications/entities/notification.entity.ts	digest_count, digest_event_times columns
backend/src/notifications/dto/notification.dto.ts	digest fields in CreateNotificationDto
backend/src/notifications/1745100000000-AddDigestColumnsToNotifications.ts	New migration
backend/src/notifications/notifications.service.spec.ts	Digest unit tests
backend/src/migration.datasource.ts	Register new migration
frontend/src/lib/notifications.ts	Notification type + mock data
frontend/src/components/notifications/NotificationItem.tsx	Digest count badge
frontend/src/components/notifications/NotificationDetail.tsx	Batched events panel
frontend/e2e/notifications.spec.ts	Digest e2e tests
backend/src/creators/creators.service.ts	Fixed searchCreators
backend/src/common/dto/paginated-response.dto.ts	total/page/totalPages
frontend/src/lib/api/creators.ts	New API client
frontend/src/app/discover/DiscoverContent.tsx	Wire real API
scripts/pg-backup-restore.sh	Backup/restore/drill script
docs/POSTGRES_BACKUP_RESTORE.md	Runbook
.github/workflows/ci.yml	db-backup-drill CI job
backend/test/rate-limit.e2e-spec.ts	Rate limit e2e tests
backend/src/app.module.ts	Register auth throttle tier
README.md	Link to backup/restore doc

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