Call the webmail inbuxa-webmail in docs and comments

The webmail repository was renamed from ihasmail-inbuxa to inbuxa-webmail
on 2026-10-05. The OAuth client id stays ihasmail-inbuxa: that is what the
server registers, so the backticked and quoted ids are unchanged.

SECURITY.md

@@ -36,7 +36,7 @@ to Stalwart Labs with credit to you, and you'll be told that has happened.
 This repository is the mail server. The web front ends have their own:
 
 - [inbuxa-admin](https://git.coffeylabs.org/inbuxa/inbuxa-admin)
-- [ihasmail-inbuxa](https://git.coffeylabs.org/inbuxa/ihasmail-inbuxa)
+- [inbuxa-webmail](https://git.coffeylabs.org/inbuxa/inbuxa-webmail)
 
 Upstream's own security documents are kept in `.github-upstream/` for
 reference. They describe Stalwart Labs' process, not this project's.