GHSA-vrqv-52x7-rm4v: Kimai's Twig function config() leaks server-wide secrets (LDAP bind password, SAML SP private key) via invoice/export templates

Kimai’s Twig sandbox (StrictPolicy, used for admin-uploaded invoice and export templates) allow-lists the config() Twig function with no key filtering. config(name) delegates to App\Configuration\SystemConfiguration::find($name), which returns arbitrary entries from the flattened kimai.config container parameter built in App\DependencyInjection\AppExtension::loadInternal(). Any admin who can upload a Twig template can therefore render server-wide secrets - the LDAP bind password, the SAML SP private key, and any other dotted configuration key populated from kimai.yaml - into the invoice or export output, which is then delivered to whoever generates an invoice or export from that template (including lower-privileged users such as teamleads with invoice permissions). This is a second, uncovered class of the same defense-in-depth issue patched in GHSA-rh42-6rj2-xwmc: the previous fix added a User-method blocklist but left the config() function unrestricted.