* feat: add upstream model update detection with scheduled sync and manual apply flows * feat: support upstream model removal sync and selectable deletes in update modal * feat: add detect-only upstream updates and show compact +/- model badges * feat: improve upstream model update UX * feat: improve upstream model update UX * fix: respect model_mapping in upstream update detection * feat: improve upstream update modal to prevent missed add/remove actions * feat: add admin upstream model update notifications with digest and truncation * fix: avoid repeated partial-submit confirmation in upstream update modal * feat: improve ui/ux * feat: suppress upstream update alerts for unchanged channel-count within 24h * fix: submit upstream update choices even when no models are selected * feat: improve upstream model update flow and split frontend updater * fix merge conflict
