Add admin location editing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

db/queries.sql

@@ -15,6 +15,9 @@ UPDATE events SET description = ? WHERE id = ?;
 -- name: UpdateEvent :exec
 UPDATE events SET title = ?, date = ?, time = ?, location = ? WHERE id = ?;
 
+-- name: UpdateEventLocation :exec
+UPDATE events SET location = ? WHERE id = ?;
+
 -- name: DeleteEvent :exec
 DELETE FROM events WHERE id = ?;