feat: add authentik admin user sync endpoint

scripts/init_schema.sql

@@ -5,6 +5,7 @@ CREATE EXTENSION IF NOT EXISTS pgcrypto;
 CREATE TABLE IF NOT EXISTS users (
   id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
   authentik_sub VARCHAR(255) NOT NULL UNIQUE,
+  authentik_user_id INTEGER,
   email VARCHAR(320),
   display_name VARCHAR(255),
   is_active BOOLEAN NOT NULL DEFAULT TRUE,

scripts/migrate_add_authentik_user_id.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users
+  ADD COLUMN IF NOT EXISTS authentik_user_id INTEGER;