feat: add VisuallyHidden component and enhance LocationDialog accessibility

web/src/components/MemoEditor/ActionButton/InsertMenu/LocationDialog.tsx

 import { LatLng } from "leaflet";
 import LeafletMap from "@/components/LeafletMap";
 import { Button } from "@/components/ui/button";
-import { Dialog, DialogClose, DialogContent } from "@/components/ui/dialog";
+import { Dialog, DialogClose, DialogContent, DialogDescription, DialogTitle } from "@/components/ui/dialog";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { Textarea } from "@/components/ui/textarea";
+import { VisuallyHidden } from "@/components/ui/visually-hidden";
 import { useTranslate } from "@/utils/i18n";
 import { LocationState } from "./types";
 
@@ -39,7 +40,15 @@ export const LocationDialog = ({
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-w-[min(28rem,calc(100vw-2rem))] !p-0">
-        <DialogClose className="hidden"></DialogClose>
+        <VisuallyHidden>
+          <DialogClose />
+        </VisuallyHidden>
+        <VisuallyHidden>
+          <DialogTitle>{t("tooltip.select-location")}</DialogTitle>
+        </VisuallyHidden>
+        <VisuallyHidden>
+          <DialogDescription>Select a location on the map or enter coordinates manually</DialogDescription>
+        </VisuallyHidden>
         <div className="flex flex-col">
           <div className="w-full h-64 overflow-hidden rounded-t-md bg-muted/30">
             <LeafletMap key={JSON.stringify(locationInitialized)} latlng={position} onChange={onPositionChange} />

web/src/components/ui/visually-hidden.tsx

+import * as React from "react";
+
+export const VisuallyHidden = React.forwardRef<HTMLSpanElement, React.HTMLAttributes<HTMLSpanElement>>(({ children, ...props }, ref) => {
+  return (
+    <span
+      ref={ref}
+      className="absolute w-px h-px p-0 -m-px overflow-hidden whitespace-nowrap border-0"
+      style={{
+        clip: "rect(0, 0, 0, 0)",
+        clipPath: "inset(50%)",
+      }}
+      {...props}
+    >
+      {children}
+    </span>
+  );
+});
+
+VisuallyHidden.displayName = "VisuallyHidden";