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-backend/MANIFEST.SKIP

@@ -0,0 +1,84 @@
+^maint/
+^tags$
+^\.last_cover_stats$
+^t.*sessions
+^.*\.log
+^.*\.swp$
+^MANIFEST\.SKIP$
+^Dockerfile$
+^zonemaster_launch$
+^\.github/
+^docs/internal-documentation/
+\.po$
+^share/[^/]*\.mo$
+^share/Zonemaster-Backend.pot$
+^share/backend_config\.ci_mysql\.ini$
+^share/backend_config\.ci_postgresql\.ini$
+^share/backend_config\.ci_sqlite\.ini$
+^share/update-po$
+^Zonemaster-Backend-[0-9.]*\.tar\.gz
+
+# PO files are not present in the distribution package, tests of those are irrelevant there.
+^t/po-files.t
+
+#!start included /usr/share/perl/5.20/ExtUtils/MANIFEST.SKIP
+# Avoid version control files.
+\bRCS\b
+\bCVS\b
+\bSCCS\b
+,v$
+\B\.svn\b
+\B\.git\b
+\B\.gitignore\b
+\b_darcs\b
+\B\.cvsignore$
+
+# Avoid VMS specific MakeMaker generated files
+\bDescrip.MMS$
+\bDESCRIP.MMS$
+\bdescrip.mms$
+
+# Avoid Makemaker generated and utility files.
+\bMANIFEST\.bak
+^Makefile$
+\bblib/
+\bMakeMaker-\d
+\bpm_to_blib\.ts$
+\bpm_to_blib$
+\bblibdirs\.ts$         # 6.18 through 6.25 generated this
+
+# Avoid Module::Build generated and utility files.
+\bBuild$
+\b_build/
+\bBuild.bat$
+\bBuild.COM$
+\bBUILD.COM$
+\bbuild.com$
+
+# Avoid temp and backup files.
+~$
+\.old$
+\#$
+\b\.#
+\.bak$
+\.tmp$
+\.#
+\.rej$
+
+# Avoid OS-specific files/dirs
+# Mac OSX metadata
+\B\.DS_Store
+# Mac OSX SMB mount metadata files
+\B\._
+
+# Avoid Devel::Cover and Devel::CoverX::Covered files.
+\bcover_db\b
+\bcovered\b
+
+# Avoid MYMETA files
+^MYMETA\.
+
+# Avoid MANIFEST test
+t/manifest.t
+
+#!end included /usr/share/perl/5.20/ExtUtils/MANIFEST.SKIP