Add media type sniffing by extension

packages/frontend/src/routes/Piece.tsx

@@ -1,5 +1,6 @@
 import type { Attachment, Piece } from "backend/database";
 import { AttachmentId, PieceId } from "common";
+import { ACCEPTED_EXTENSIONS } from "common/MediaType";
 import { ELYSIA_FORM_DATA } from "elysia";
 import { FormEventHandler, useId, useReducer, useRef, useState } from "react";
 import { Link, useParams } from "react-router-dom";
@@ -254,6 +255,7 @@ function AttachmentForm(props: AttachmentForm.Props) {
 					const file = e.target.files?.item(0) ?? null;
 					reduce(FileReducer.setFile(file));
 				}}
+				accept={ACCEPTED_EXTENSIONS}
 			/>
 			<Button type="submit">
 				Dodaj