feat: support group invite privacy verification

docs/sql/IM-隐私设置邀我入群验证SQL.sql

@@ -0,0 +1,17 @@
+-- Add personal privacy switch for requiring approval when others invite the user into a group.
+-- Default is off to preserve existing behavior.
+
+SET @im_sql = (
+  SELECT IF(
+    COUNT(*) = 0,
+    'ALTER TABLE tinode.im_user_privacy_settings ADD COLUMN group_invite_verification TINYINT NOT NULL DEFAULT 0 AFTER read_receipts',
+    'SELECT 1'
+  )
+  FROM information_schema.columns
+  WHERE table_schema = 'tinode'
+    AND table_name = 'im_user_privacy_settings'
+    AND column_name = 'group_invite_verification'
+);
+PREPARE im_stmt FROM @im_sql;
+EXECUTE im_stmt;
+DEALLOCATE PREPARE im_stmt;