fix: pin guacamole/guacd to 1.6.0 and disable Watchtower to prevent schema breakage

Watchtower pulled a newer guacamole:latest image whose JDBC extension expected
tables not present in the existing DB (guacamole_user_attribute etc.). Fixed by
reinitializing the DB with the official 1.6.0 schema (001-create-schema.sql +
002-create-admin-user.sql) and pinning both guacamole and guacd to 1.6.0 with
com.centurylinklabs.watchtower.enable=false to prevent recurrence.

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

compose/hf-pdocker-01/guacamole/docker-compose.yml

@@ -1,6 +1,6 @@
 services:
   guacamole:
-    image: guacamole/guacamole:latest
+    image: guacamole/guacamole:1.6.0
     container_name: guacamole
     restart: unless-stopped
     environment:
@@ -18,6 +18,8 @@ services:
         condition: service_healthy
     mem_limit: 512M
     memswap_limit: 512M
+    labels:
+      - "com.centurylinklabs.watchtower.enable=false"
     healthcheck:
       test: ["CMD-SHELL", "curl -f http://localhost:8080/guacamole/ || exit 1"]
       interval: 30s
@@ -31,13 +33,15 @@ services:
         max-file: "3"
 
   guacd:
-    image: guacamole/guacd:latest
+    image: guacamole/guacd:1.6.0
     container_name: guacd
     restart: unless-stopped
     networks:
       - guacamole-internal
     mem_limit: 512M
     memswap_limit: 512M
+    labels:
+      - "com.centurylinklabs.watchtower.enable=false"
     logging:
       driver: "json-file"
       options: