fix(plugin): correct telemetry server path for installed plugin

- Resolve telemetry.mjs relative to installed plugin root
- Update installer messaging from challengeUuid to apiKey
- Document correct OpenClaw plugin entry config structure

plugin/index.ts

@@ -48,7 +48,7 @@ export default function register(api: PluginAPI, config: PluginConfig) {
     logger.warn('API authentication will fail. Generate apiKey from HarborForge Monitor admin.');
   }
 
-  const serverPath = join(__dirname, '..', 'server', 'telemetry.mjs');
+  const serverPath = join(__dirname, 'server', 'telemetry.mjs');
 
   if (!existsSync(serverPath)) {
     logger.error('Telemetry server not found:', serverPath);