feat: Add Status Bar Item for NPM Up-to-Date feature observability and manual refresh

Currently, the `NpmUpToDateFeature` runs completely in the background (`headless`), making it difficult for users to know the current state of their package checks or manually trigger a refresh.

#### Proposed Changes:
1. **Create a Status Bar Item:** Add a dedicated status bar component to reflect the current status (e.g., checking, up-to-date, or update available).
2. **Manual Refresh Action:** Allow users to click the status bar item to trigger an immediate check manually.
3. **Configuration & Lifecycle Management:** Properly dispose of and update the status bar item when the feature is enabled/disabled via workspace settings or during extension deactivation.