feat: add full Zonemaster stack with Docker and Spanish UI

- Clone all 5 Zonemaster component repos (LDNS, Engine, CLI, Backend, GUI)
- Dockerfile.backend: 8-stage multi-stage build LDNS→Engine→CLI→Backend
- Dockerfile.gui: Astro static build served via nginx
- docker-compose.yml: backend (internal) + frontend (port 5353)
- nginx.conf: root redirects to /es/, /api/ proxied to backend
- zonemaster-gui/config.ts: defaultLanguage set to 'es' (Spanish)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

zonemaster/docs/public/specifications/tests/Nameserver-TP/nameserver09.md

@@ -0,0 +1,39 @@
+## NAMESERVER09: Testing QNAME case sensitivity
+
+### Test case identifier
+NAMESERVER09 Verify whether the authoritative nameserver returns same results
+for equivalent names with different cases in the request.
+
+
+### Objective
+There has been cases where the nameservers respond with complete
+case-sensitivity (in violation of the DNS standards): that is, they match the
+exact case of the name in the response; but return different results for
+equivalent names with different cases in the request (typically NXDOMAIN). 
+
+
+### Inputs
+The domain name to be tested.
+
+### Ordered description of steps to be taken to execute the test case
+1. Retrieve all address records for all the name servers using [Method 
+   4](../Methods.md) and [Method 5](../Methods.md).
+2. Send a query with the input string in a mixed case (e.g. wWW.iETF.oRG) to
+   each of the name server IP address found in step 1. 
+3. If the "answer" flag is greater than 0, remember the "answer" section, else
+   remember the status flag. 
+4. Send another query with an alternative mixed case (e.g. Www.Ietf.Org) to each
+   of the name server found in step 1.
+5. If the "answer" flag is greater than 0, remember the "answer" section, else
+   remember the status flag. 
+6. Compare the results remembered in step3 and step5.
+7. If the results in step 6 are not equal, the test case fails.
+
+### Outcome(s)
+The test case passes only if the results of all queries are exactly the same. 
+
+### Special procedural requirements
+None.
+
+### Intercase dependencies
+None.