feat: image storage generalization, user profile, and federation polish

- Replace PosterStorage with generic ImageStorage port (IMAGE_STORAGE_BACKEND/PATH env vars)
- Rename poster-storage crate to image-storage; serve at /images/{*key}
- Add bio and avatar_path to User model (migration 0009_user_profile)
- update_profile use case with avatar upload, mime validation, old avatar cleanup
- GET/PUT /api/v1/profile and GET/POST /settings/profile HTML page
- Enrich AP Person actor with summary, icon, url, discoverable fields
- Store remote actor avatar_url (migration 0010_ap_remote_actor_avatar)
- Shared inbox delivery via collect_inboxes deduplication
- Broadcast Update(Person) to followers on UserUpdated event
- Paginated outbox: OrderedCollection + OrderedCollectionPage with cursor
- Announce/boost tracking in ap_announces table (migration 0011_ap_announces)

crates/worker/Cargo.toml

@@ -30,7 +30,7 @@ async-trait = { workspace = true }
 auth = { workspace = true }
 metadata = { workspace = true }
 poster-fetcher = { workspace = true }
-poster-storage = { workspace = true }
+image-storage = { workspace = true }
 poster-sync = { workspace = true }
 export = { workspace = true }
 importer = { workspace = true }