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/internal/functional-tests/Behavior-TP/behavior06.md

@@ -0,0 +1,43 @@
+## BEHAVIOR06: Timestamps display
+
+### Test case identifier
+
+**BEHAVIOR06:** Timestamps display
+
+### Objective 
+This test is to verify whether the engine displays timestamps on the test being
+run
+
+### Inputs
+
+The domain to be tested. 
+
+### Ordered description of steps to be taken to execute the test case
+
+1. A valid domain is verified using Zonemaster CLI with appropriate options as
+see in the appendix
+2. If the query don’t show timestamp in the results,  the test returns FAIL
+
+### Results
+
+### Appendix
+```
+zonemaster-cli --time afnic.fr
+Seconds Level     Message
+======= ========= =======
+  17.89 NOTICE    SOA 'mname' nameserver (dnsmaster.nic.fr) is not listed in
+"parent" NS records for tested zone (ns1.nic.fr;ns2.nic.fr;ns3.nic.fr).
+  17.90 NOTICE    SOA 'refresh' value (7200) is less than the recommended one
+(14400).
+  17.90 NOTICE    SOA 'retry' value (1800) is less than the recommended one
+(3600).
+sandoche@eryx:~$ zonemaster-cli afnic.fr
+Seconds Level     Message
+======= ========= =======
+   8.16 NOTICE    SOA 'mname' nameserver (dnsmaster.nic.fr) is not listed in
+"parent" NS records for tested zone (ns1.nic.fr;ns2.nic.fr;ns3.nic.fr).
+   8.16 NOTICE    SOA 'refresh' value (7200) is less than the recommended one
+(14400).
+   8.17 NOTICE    SOA 'retry' value (1800) is less than the recommended one
+(3600).
+```