[BUG] Notes Panel: Close button is non-functional and misleading when only one note exists

[arindam-sahoo]

Description:
In the Notes panel, when there is only a single note left in the tabs, clicking the close (x) button on the active tab does nothing. The deletion is blocked in the store because the application requires at least one note to exist. However, the close button remains visible and clickable, creating a confusing user experience where the action appears broken.

To Reproduce
Steps to reproduce the behavior:

1. Open KoBar and navigate to the Notes panel.
2. If there are multiple notes, close them until only one note remains.
3. Click the close (x) button on the last remaining note tab.
4. See error: The delete confirmation popup appears, but confirming the deletion does not delete the note.

Expected behavior
When only a single note is present (excluding the "Settings" tab), the close (x) button should either:

1. Not be shown on the tab.
2. Be disabled, and displaying a tooltip on hover explaining that a minimum of one note must be kept (e.g., "At least one note must exist").

Environment (please complete the following information):

• OS: Windows 10
• KoBar Version: v1.0.21