feat: discoverability (NodeInfo, hashtags) and moderation (domain/actor blocking)

- NodeInfo at /.well-known/nodeinfo + /nodeinfo/2.0
- Hashtags #MoviesDiary + #MovieTitle on review posts; /tags/{tag} redirect
- Domain blocking: blocked_domains table, admin API + HTML, inbox enforcement
- Per-actor blocking: blocked_actors table, user API + HTML, BlockActivity send/receive
- Delivery filter excludes blocked actors and blocked-domain inboxes

crates/domain/src/ports.rs

@@ -116,6 +116,7 @@ pub trait DiaryRepository: Send + Sync {
         movie_id: &MovieId,
         page: &PageParams,
     ) -> Result<Paginated<FeedEntry>, DomainError>;
+    async fn count_local_posts(&self) -> Result<u64, DomainError>;
 }
 
 #[async_trait]