fix: enforce strict config validation

src/plugin-sdk/index.ts

@@ -55,6 +55,7 @@ export type {
 export type { ChannelConfigSchema, ChannelPlugin } from "../channels/plugins/types.plugin.js";
 export type { ClawdbotPluginApi } from "../plugins/types.js";
 export type { PluginRuntime } from "../plugins/runtime/types.js";
+export { emptyPluginConfigSchema } from "../plugins/config-schema.js";
 export type { ClawdbotConfig } from "../config/config.js";
 export type { ChannelDock } from "../channels/dock.js";
 export { getChatChannelMeta } from "../channels/registry.js";