fix(docker): generic naming (mosaic-*), env-var-only config, no hardcoded values

- Renamed all jarvis-* to mosaic-* (generic for any deployment)
- Config files are .json.template with ${VAR} placeholders
- entrypoint.sh renders templates via envsubst at startup
- Ollama is optional: set OLLAMA_BASE_URL to auto-inject provider
- Model is configurable via OPENCLAW_MODEL env var
- No hardcoded IPs, keys, model names, or user preferences
- Updated README with full env var reference

docker/openclaw-instances/mosaic-main.json.template

@@ -0,0 +1,19 @@
+{
+  "gateway": {
+    "mode": "local",
+    "port": 18789,
+    "bind": "lan",
+    "auth": { "mode": "token" },
+    "http": {
+      "endpoints": {
+        "chatCompletions": { "enabled": true }
+      }
+    }
+  },
+  "agents": {
+    "defaults": {
+      "workspace": "/home/node/workspace",
+      "model": { "primary": "${OPENCLAW_MODEL:-zai/glm-5}" }
+    }
+  }
+}