docs(readme): credit @SIENSIS for the Pi-hole login crash report

Author: bertugfahriozer

README.md

@@ -230,5 +230,6 @@ Thanks to the community members who report functional bugs and help us catch reg
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 | **[spreaderman](https://github.com/spreaderman)** | Reported two installation-blocking regressions in v0.31.10.0: the web installer returning `404 GET install/dbsetup` after the configuration step, and `php spark ci4ms:setup` aborting on the `users.profileIMG` migration due to a `TEXT` column with a default value (rejected by MySQL/MariaDB strict mode). | May 2026 |
 | **[SIENSIS](https://github.com/SIENSIS)** | Reported the fresh-install web installer failing silently because `.env` is written mid-request: migrations ran against an empty database name and the encrypter raised a "needs a starter key" error. | Jul 2026 |
+| **[SIENSIS](https://github.com/SIENSIS)** | Reported that every login crashed with a 500 when a DNS-level blocker (e.g. Pi-hole) or an outage made the `ip-api.com` geo lookup unreachable — a failed fetch returned `false` and `json_decode(false)` raised an uncaught `TypeError` under `strict_types`. This led to replacing the third-party call with a local, opt-in geo lookup. | Jul 2026 |
 
 > Found a non-security bug? Please [open an issue](https://github.com/ci4-cms-erp/ci4ms/issues) with reproduction steps.