Add sablier override for scale-to-zero

Labels for web/prosody/jicofo/jvb to join jeffsi-meet sablier group.
Disables traefik on web (routing handled by sablier dynamic config).

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

docker-compose.sablier.yml

@@ -0,0 +1,18 @@
+services:
+  web:
+    labels:
+      - "sablier.enable=true"
+      - "sablier.group=jeffsi-meet"
+      - "traefik.enable=false"
+  prosody:
+    labels:
+      - "sablier.enable=true"
+      - "sablier.group=jeffsi-meet"
+  jicofo:
+    labels:
+      - "sablier.enable=true"
+      - "sablier.group=jeffsi-meet"
+  jvb:
+    labels:
+      - "sablier.enable=true"
+      - "sablier.group=jeffsi-meet"