feat: push OpenClaw metadata to Monitor bridge periodically

- MonitorBridgeClient gains pushOpenClawMeta() method for POST /openclaw
- OpenClawMeta interface defines version/plugin_version/agents payload
- Plugin pushes metadata on gateway_start (delayed 2s) and periodically
- Interval aligns with reportIntervalSec (default 30s)
- Pushes are non-fatal — plugin continues if Monitor is unreachable
- Interval cleanup on gateway_stop
- Updated monitor-server-connector-plan.md with new architecture

plugin/core/monitor-bridge.d.ts

@@ -36,6 +36,20 @@ export declare class MonitorBridgeClient {
     constructor(port: number, timeoutMs?: number);
     health(): Promise<MonitorHealth | null>;
     telemetry(): Promise<MonitorTelemetryResponse | null>;
+    /**
+     * POST OpenClaw metadata to the Monitor bridge so it can enrich
+     * its heartbeat uploads with OpenClaw version, plugin version,
+     * and agent information.
+     */
+    pushOpenClawMeta(meta: OpenClawMeta): Promise<boolean>;
     private fetchJson;
 }
+/**
+ * OpenClaw metadata payload sent to the Monitor bridge.
+ */
+export interface OpenClawMeta {
+    version: string;
+    plugin_version: string;
+    agents?: any[];
+}
 //# sourceMappingURL=monitor-bridge.d.ts.map