Description:
Add a keyword search control to the Notes (home) page that filters notes for the logged-in user. Include a clearly labeled "Show all notes" button that clears the search input and restores the full notes list when clicked. The feature must work without a full page reload when possible and preserve existing add/delete note behavior.
Motivation:
Users need an easy way to search their notes and then quickly return to the full list without manually clearing the input or fiddling with the URL.