Move hardcoded secrets to .env files for dns-updateip, docker-registry, openclaw

- dns-updateip: APIKEY now uses ${APIKEY} substitution
- docker-registry: SECRET_KEY_BASE now uses ${SECRET_KEY_BASE} substitution
- openclaw: OPENCLAW_GATEWAY_TOKEN now uses ${OPENCLAW_GATEWAY_TOKEN} substitution
- Add .env.example templates for backrest, dns-updateip, docker-registry, openclaw

openclaw/.env.example

@@ -1,7 +1,2 @@
-# Generate a random token for gateway authentication
-# You can use: openssl rand -hex 32
-OPENCLAW_GATEWAY_TOKEN=your-gateway-token-here
-
-# Ollama Configuration
-# OpenClaw will connect to Ollama running at http://ollama:11434
-# Make sure Ollama is running and has models pulled (e.g., llama3, mistral)
+# OpenClaw Gateway Token (auto-generated or set manually)
+OPENCLAW_GATEWAY_TOKEN=your_gateway_token

openclaw/docker-compose.yml

@@ -11,7 +11,7 @@ services:
       - TZ=America/New_York
       - PUID=1000
       - PGID=1000
-      - OPENCLAW_GATEWAY_TOKEN=27d4e63adce6c8f7c5396e8ca3f9ec5e6ff590077247fb11da03a8684ee3c711
+      - OPENCLAW_GATEWAY_TOKEN=${OPENCLAW_GATEWAY_TOKEN}
       - OPENCLAW_GATEWAY_BIND=lan
       - OPENCLAW_AGENT_PROVIDER=ollama
       - OPENCLAW_AGENT_MODEL=llama3