feat(wave2): add @mosaic/openclaw-context plugin to monorepo

- OpenClaw → OpenBrain context engine plugin migrated from mosaic/openclaw-openbrain-context
- Depends on @mosaic/types workspace:*
- Typecheck passing

plugins/openclaw-context/src/index.ts

@@ -0,0 +1,31 @@
+import {
+  OPENBRAIN_CONTEXT_ENGINE_ID,
+  OPENBRAIN_PLUGIN_ID,
+  OPENBRAIN_PLUGIN_VERSION,
+} from "./constants.js";
+import { OpenBrainContextEngine } from "./engine.js";
+import type { OpenClawPluginApi } from "./openclaw-types.js";
+
+export { OPENBRAIN_CONTEXT_ENGINE_ID } from "./constants.js";
+export { OpenBrainContextEngine } from "./engine.js";
+export { OpenBrainConfigError, OpenBrainHttpError, OpenBrainRequestError } from "./errors.js";
+export { OpenBrainClient } from "./openbrain-client.js";
+export type { OpenBrainContextEngineConfig } from "./engine.js";
+export type { OpenClawPluginApi } from "./openclaw-types.js";
+
+export function register(api: OpenClawPluginApi): void {
+  api.registerContextEngine(OPENBRAIN_CONTEXT_ENGINE_ID, () => {
+    const deps = api.logger !== undefined ? { logger: api.logger } : undefined;
+    return new OpenBrainContextEngine(api.pluginConfig, deps);
+  });
+}
+
+const plugin = {
+  id: OPENBRAIN_PLUGIN_ID,
+  name: "OpenBrain Context Engine",
+  version: OPENBRAIN_PLUGIN_VERSION,
+  kind: "context-engine",
+  register,
+};
+
+export default plugin;