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/adapters/activitypub/src/event_handler.rs

@@ -92,6 +92,7 @@ impl ActivityPubEventHandler {
             movie_title,
             release_year,
             poster_url,
+            &self.base_url,
         );
         let json = serde_json::to_value(obj)?;