fix: quote nginx cache regex

README.md

@@ -77,7 +77,7 @@ Prerequisites:
 - Traefik attached to the existing external Docker network `internal`;
 - a Traefik HTTPS entrypoint named `websecure`;
 - a certificate resolver named `netcup`;
-- DNS for `toolbax.add-ideas.de` pointing to that Traefik instance; and
+- DNS for `toolbox.add-ideas.de` pointing to that Traefik instance; and
 - outbound HTTPS access to `git.add-ideas.de` while the image is built.
 
 Deploy a fresh clone with:
@@ -90,11 +90,11 @@ docker compose ps
 ```
 
 No host port is published. Traefik routes
-`https://toolbax.add-ideas.de` to nginx on the shared network at port 8080 and
+`https://toolbox.add-ideas.de` to nginx on the shared network at port 8080 and
 obtains its TLS certificate through `netcup`. The hostname, network, resolver,
 release version, and matching checksum can be overridden through environment
 variables; copy `.env.example` to `.env` only when an override is needed. For
-example, set `TOOLBOX_HOST=toolbox.add-ideas.de` if that spelling is preferred.
+example, set `TOOLBOX_HOST=staging.toolbox.add-ideas.de` for a staging host.
 
 The external network is deliberately not created by this project. Creating a
 private project-local network would prevent an independently managed Traefik