Add clearable search button to home search bar

[Subhash-2005]

Updated [search_card.dart]
Converted SearchCard to a StatefulWidget
Added an interactive clear button that appears when search text is entered
Clears text when the button is tapped
Updated [README.md]
with a note describing the new feature

[gemini-code-assist]

Code Review

This pull request converts the SearchCard widget into a StatefulWidget to introduce a clearable search field functionality. Key changes include adding a TextEditingController listener to track input and dynamically switching the suffix icon between a clear button and a filter icon. Review feedback suggests standardizing the README header, optimizing the text change listener to prevent unnecessary state updates, and adjusting the suffix icon implementation to maintain consistent UI styling when the field is empty.