feat(mcp): подготовить сервер и доступ к приёмке

backend/drizzle/0023_mcp_protocol_limits.sql

@@ -0,0 +1,6 @@
+BEGIN;
+CREATE TABLE IF NOT EXISTS mcp_unauthorized_buckets (
+ bucket timestamptz NOT NULL, client_hash text NOT NULL, reason text NOT NULL,
+ attempts integer NOT NULL DEFAULT 1, PRIMARY KEY(bucket,client_hash,reason)
+);
+COMMIT;