Issue #3610500: Refresh the documentation, announce every lifecycle outcome, index the payment table, and add French translations

Follows the issue summary. Documentation rewritten to the current API; token-charge and decline outcomes now dispatch events; capture/refund/cancel advance under a row lock; Worldline keeps the reference on a rejected payment, guards the webhook by gateway, and memoizes the client; the payment table gets a composite index and the payments view a proper state dropdown; state and entity labels made translatable and French translations added for all submodules. All existing and new kernel tests pass (33 tests, 187 assertions); phpcs, phpstan and cspell clean locally.