feat(db): align movie state with canonical MediaState (#85)

crates/arr-daemon/src/grab.rs

@@ -352,7 +352,7 @@ impl GrabAction {
         .fetch_optional(database.pool())
         .await?;
         sqlx::query!(
-            "UPDATE movies SET state = 'grabbed',
+            "UPDATE movies SET state = 'downloading',
                     updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')
              WHERE id = ?",
             movie.id
@@ -852,7 +852,7 @@ mod tests {
             .fetch_one(database.pool())
             .await
             .unwrap();
-        assert_eq!(state, "grabbed");
+        assert_eq!(state, "downloading");
     }
 
     /// The failure mode the issue names: killed after the torrent is sent and