Animated stickers

Sticker assets have two independent axes:

• image_source = 'managed' | 'static' says where the bytes come from. managed assets use the image-asset registry; static assets are packaged under apps/web/public/stickers/.
• media_kind = 'still' | 'animated' says whether a sticker contains motion. Do not use static as a synonym for a still image in new fields, variables, or product copy.

Animated GIF, animated WebP, and APNG are supported for managed creator packs. Packaged sticker packs remain still-only for the initial release. Lottie/TGS, WebM/video stickers, animated avatars/covers, agent-sent stickers, and typed SDK changes to stickerMetadata are outside this release.

sticker_packs.has_animated is a denormalized browse/review flag maintained in the same transaction as sticker additions and deletions. Historical GIFs are classified by the required schema migration. Historical animated WebP/APNG assets require the storage-sniffing operational backfill described in the animated-sticker backfill runbook.

Operational procedure, dry-run/apply commands, pause/resume semantics, and verification SQL are in runbooks/animated-sticker-backfill.md.