feat(openclaw): add workerHost config for Docker deployments

When the OpenClaw gateway runs in Docker and the claude-mem worker runs
on the host, localhost:37777 is unreachable from inside the container.

Add a workerHost config option (default: 127.0.0.1) so users can set it
to host.docker.internal for Docker-based deployments.

Changes:
- Add workerHost to ClaudeMemPluginConfig interface
- Read workerHost from plugin config in plugin entry point
- Update workerBaseUrl to use configurable host
- Add workerHost to openclaw.plugin.json config schema
- Update startup log to show configured host

openclaw/openclaw.plugin.json

@@ -27,6 +27,11 @@
         "default": 37777,
         "description": "Port for Claude-Mem worker service"
       },
+      "workerHost": {
+        "type": "string",
+        "default": "127.0.0.1",
+        "description": "Hostname for Claude-Mem worker service. Set to host.docker.internal when the gateway runs in Docker and the worker runs on the host."
+      },
       "project": {
         "type": "string",
         "default": "openclaw",