Sync (`/api/sync/*`)

Route	Purpose
`POST /api/sync/handle-update`	User decision on a pending sync record: `accept` \| `reject` \| `ignore`; target user must match `target_user_uuid`; accept merges via `generateContentDiff` / incremental snapshot into unified modules (`src/models/unified-modules-simple`, `src/lib/content-diff`)
`GET /api/sync/pending-updates`	List pending records for the current user
`POST /api/sync/trigger-update-check`	Trigger server-side update check
`POST /api/sync/batch-handle-update`	Batch handle
`POST /api/sync/create-invitation`	Create sync/share invitation (admin or permitted flows — see route for guards)

Models: src/models/sync.ts (updateSyncRecordStatus, getSyncRecordWithUserInfo, etc.).

Invite & codes

Route	Purpose
`POST /api/update-invite`	Update user invite code / invite metadata (see route + `src/services` usage)
`POST /api/update-invite-code`	Dedicated invite-code update
`GET/POST .../admin/invitations`	Admin invitation management
`POST /api/user/generate-exclusive-token`	Generate exclusive token for user
`POST /api/user/update-exclusive-token`	Update token
`POST /api/resolve-exclusive-token`	Resolve token server-side
`POST /api/user/copy-from-referrer`	Copy content from referrer when joining

Source user change creates a sync_record with status pending.
Target opens pending list → POST handle-update with accept.
Server applies diff to unified modules; status updated; optional blacklist side effects (notification-blacklist).

src/app/api/sync/**
src/app/api/update-invite/route.ts, update-invite-code/route.ts
src/app/api/user/generate-exclusive-token/route.ts, update-exclusive-token/route.ts, copy-from-referrer/route.ts
src/app/api/resolve-exclusive-token/route.ts
src/models/sync.ts, src/lib/content-diff.ts

Environment

DATABASE_URL
ADMIN_EMAILS — when create-invitation or related routes are admin-gated (verify in the specific route.ts).

Database (src/db/schema.ts)

content_sync_records, user_invitations, user_notification_blacklist
users — invite_code, invited_by, exclusive_link_token
On accept: user_profiles, user_module_configs, user_module_website_relations, user_custom_module_types, user_custom_websites, etc.