No-accounts app, so favorites/saved-searches/hidden-list/watch-progress live
per-device (keyed by X-Device-Id). Users asked how to move them to a new phone.
Backend: POST /me/import/{source_device} copies all device-scoped tables from a
source device to the caller (dedup via NOT EXISTS, new UUIDs for id-PK tables like
saved_searches). Copy not move, so the old phone keeps everything; idempotent. The
device_id is a random UUID so knowing it is the authorization (fine for a keyless app).
Mobile: Settings -> "Backup & sync" shows this device's sync code (copy button) and a
Restore field to paste the other device's code; invalidates favorites queries after.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Public instance has no accounts, so all user state was GLOBAL in DB — new users
saw/overwrote each other's (and Jan's) favorites, watched badges and blacklists
(bug 2026-06-10). Add device_id (VARCHAR 64) to 9 state tables with composite PK
(device_id, entity_id); app sends X-Device-Id header (get_device_id dep). All
favorites/scene-favorites/blacklist/watch + scene&movie list/detail (is_favorite,
watched, blacklist-hide) now filter by device. Existing rows backfilled to
'legacy-shared'; POST /me/adopt-legacy reassigns them to the caller once. Old
clients (no header) map to legacy-shared so they keep working until OTA updates.
Migration 0022: add col, backfill, composite PK. Verified on prod: 967 progress
rows preserved, device isolation holds (new device sees none of legacy state).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
