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/adapters/activitypub/src/user_adapter.rs

@@ -13,6 +13,8 @@ impl ApUserRepository for DomainUserRepoAdapter {
         Ok(self.0.find_by_id(&user_id).await?.map(|u| ApUser {
             id: u.id().value(),
             username: u.username().value().to_string(),
+            bio: u.bio().map(|s| s.to_string()),
+            avatar_path: u.avatar_path().map(|s| s.to_string()),
         }))
     }
 
@@ -23,6 +25,8 @@ impl ApUserRepository for DomainUserRepoAdapter {
         Ok(self.0.find_by_username(&uname).await?.map(|u| ApUser {
             id: u.id().value(),
             username: u.username().value().to_string(),
+            bio: u.bio().map(|s| s.to_string()),
+            avatar_path: u.avatar_path().map(|s| s.to_string()),
         }))
     }
 }