Public web-only release: SvxPortal front-end + auth backend, install templates and INSTALL.md

Stripped from the internal repo: per-box deploy trees, Go services (nodelist/astmeta/proxy/svxdr),
deploy/sync scripts and all secrets. Config templates for nginx, PHP-FPM, Redis and tmpfiles
live in install/ with CHANGEME placeholders.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

install/redis-svxportal.conf

@@ -0,0 +1,21 @@
+# Dedicated Redis instance for SvxPortal (unix socket only, no TCP port).
+# Install:  sudo cp install/redis-svxportal.conf /etc/redis/redis-svxportal.conf
+#           sudo mkdir -p /var/lib/redis-svxportal && sudo chown redis:redis /var/lib/redis-svxportal
+#           sudo systemctl enable --now redis-server@svxportal
+# Debian/Ubuntu ship the redis-server@.service template; the instance name maps to
+# /etc/redis/redis-<name>.conf. Replace CHANGEME with a long random password and put
+# the same value in auth/config.php (redis.password).
+port 0
+unixsocket /run/redis-svxportal/redis.sock
+unixsocketperm 770
+daemonize no
+supervised systemd
+pidfile /run/redis-svxportal/redis-server.pid
+logfile /var/log/redis/redis-svxportal.log
+dir /var/lib/redis-svxportal
+requirepass CHANGEME
+maxmemory 512mb
+maxmemory-policy noeviction
+save 900 1
+save 300 10
+save 60 10000