Add a stage branch deploy beside production on z00.

Pushing stage runs CI and deploys to stage.transcribe.z00.nu with its own data, Reverb credentials, and Caddy network.

.env.example

@@ -66,7 +66,7 @@ AWS_USE_PATH_STYLE_ENDPOINT=false
 
 VITE_APP_NAME="${APP_NAME}"
 
-# Laravel Reverb (WebSockets). Browser uses VITE_*; server publish uses REVERB_HOST.
+# Laravel Reverb (WebSockets). Browser uses Blade meta (reverb.client) with VITE_* fallback.
 REVERB_APP_ID=andytranscribe
 REVERB_APP_KEY=andytranscribe-key
 REVERB_APP_SECRET=andytranscribe-secret
@@ -75,11 +75,19 @@ REVERB_PORT=8080
 REVERB_SCHEME=http
 REVERB_SERVER_HOST=0.0.0.0
 REVERB_SERVER_PORT=8080
+# Public Echo target (z00 stage/prod set these in the instance .env).
+# REVERB_PUBLIC_HOST=reverb.transcribe.z00.nu
+# REVERB_PUBLIC_PORT=443
+# REVERB_PUBLIC_SCHEME=https
 
 # Host ports for docker compose (FrankenPHP app, Reverb WS, Whisper)
 APP_HOST_PORT=8080
 REVERB_HOST_PORT=8081
 WHISPER_HOST_PORT=8090
+# Unique per Compose instance on a shared Docker host (prod default keeps existing names).
+# CONTAINER_PREFIX=andytranscribe
+# CADDY_NETWORK=caddy-proxy-manager-test_caddy-test-network
+# PUBLIC_APP_URL=https://transcribe.z00.nu
 
 VITE_REVERB_APP_KEY="${REVERB_APP_KEY}"
 VITE_REVERB_HOST=localhost