#7106: fix: openclaw update includes external npm-installed plugins

**AI Assisted** **Tested** ## Summary `openclaw update` now properly updates externally installed npm plugins. ## Problem Running `openclaw update` would not update plugins installed via `openclaw plugins install <npm-package>`. Only bundled plugins were being updated. **Steps to reproduce:** 1. Install an external npm plugin: `openclaw plugins install openclaw-penfield` 2. A new version is published to npm 3. Run `openclaw update` 4. Plugin is NOT updated (stays on old version) ## Root Cause `syncPluginsForUpdateChannel()` only processes bundled plugins. When `updateNpmInstalledPlugins()` was called without explicit plugin IDs, it iterated over the post-sync config which doesn't include external npm plugins. ## Solution Capture npm plugin IDs from config BEFORE sync runs, then pass them explicitly to `updateNpmInstalledPlugins()`. ## Tests - [x] Tested with openclaw-penfield plugin installed from npm - [x] Verified `openclaw update` now attempts to fetch new version - [ ] Existing unit tests pass