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/postgres/migrations/0012_blocked_domains.sql

@@ -0,0 +1,5 @@
+CREATE TABLE blocked_domains (
+    domain     TEXT PRIMARY KEY,
+    reason     TEXT,
+    blocked_at TEXT NOT NULL
+);

crates/adapters/postgres/migrations/0013_blocked_actors.sql

@@ -0,0 +1,6 @@
+CREATE TABLE blocked_actors (
+    local_user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    remote_actor_url TEXT NOT NULL,
+    blocked_at       TEXT NOT NULL,
+    PRIMARY KEY (local_user_id, remote_actor_url)
+);

crates/adapters/postgres/src/lib.rs

@@ -766,6 +766,16 @@ impl DiaryRepository for PostgresRepository {
             offset: page.offset,
         })
     }
+
+    async fn count_local_posts(&self) -> Result<u64, DomainError> {
+        let count: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM reviews WHERE remote_actor_url IS NULL"
+        )
+        .fetch_one(&self.pool)
+        .await
+        .map_err(Self::map_err)?;
+        Ok(count as u64)
+    }
 }
 
 #[async_trait]