Add “Project Category” metadata to each idea for better organization and filtering

[Dippp10]

@florinpop17 ji, Currently, each project idea markdown file in the /Projects directory includes details such as Tier, Description, User Stories, and Bonus Features, but there is no field indicating the type or category of project (e.g., API, Frontend, Game, Productivity, Utility).

Adding a “Category” metadata field would help readers quickly identify project domains and improve repo navigation — especially since the list has grown very large.

[Dippp10]

@florinpopji, do assign above hackoctoberfest-accepted label to above issue .......do assign issue number 1050 to me